Help Diagnose my intermittant Missing Problem

Intermittant Missing Problem/Slugishness

I've had a missing/lack of power/CEL problem for a little bit, recently its become much more troublesome.

Truck
Base: 1997 Mercury Mountaineer 5.0 302 V8. 4R70W Automatic.
Mods: see link below for Elite Registry

Symptoms Summary:
- The computer will routinely generate codes P0300 - Random Misfire and P0340 - Camshaft Position Sensor Failure.
-The truck feels sluggish, like its towing a heavy trailer (i looked... its not) or the breaks are dragging (they're not), or its not running on all cylinders.
-The truck smells like its running very rich. When I back up, It smells like latex paint or turpentine. I've been filling up at several different gas stations, all high volume and no difference in smell. The truck has been averaging about 10 miles per gallon in mixed driving, it used to get around 13.
- There is often a surging or bucking. Sometimes it is minor, other times VERY pronounced. This is usually when the CEL is set off.
-The last two times I filled up with fuel from the same high volume Sunoco station, about 15min/3miles later the CEL will be thrown and the truck will run like crap. It feels like its running on half its cylinders, won't idle, shakes, very slow, etc. There was a very strong smell of gas in the cab as well. I'm thinking canister purge system? Both days it was around 75 degrees out, and I was in stop/go traffic.

Parts Installed in effort to correct problem:
- I have installed a new Camshaft Position sensor, but the P0340 continues to be thrown.
- It has Bosch platinum plugs, and Autozone 8mm Silicon wires within the past 2000 miles.
- Fuel filter was replaced about 1.5years/14,000miles ago
- Seafoamed through brake booster hose last night
- MAC open air cleaner last summer

Tests Preformed so far:
-Vacuum: At hot idle it reads steady at 14.5-15psi. There is a small, gradual fluctuation of the needle that takes about 2 seconds to complete.
-Rail Fuel Pressure: At hot idle is steady at 36psi. Engine off it is 40psi.
-Connecting my OBD-2 scan tool (Alex Peper's computer interface), I have found some interesting results:
1) TPS: Set at the ideal 0.96 volts, the computer reads 18% Open. Set at .63volts, the computer reads 12% open. This is the lowest it will go without unplugging the sensor. If I disconnect it, the value does drop to 0.0%, and the CEL will be thrown.
2) Engine Load: The engine load percent value is around 35% for idle both in and out of gear. It goes to about 50% load by 1500rpm, and 90% load at 2500 rpm. Seems High. OBD-2 Calculated Engine Load is a funtion of airflow, barometric pressure, and stored values.
3) O2 sensor: Seems to be ok, fluctuating between 0.065 and 0.745volts on both banks.
4) Fuel Trims: While driving at 1600 rpm, engine load 54.5%, the short term is 1.6, and the long term is -7.8. On the drive, the long terms were as low as -11.17. The shorts were around 4.7

I'm not sure how to interpret all this data I now have availible to me with the scanner! I can report a lot more, as well as send the scan files to you showing the sensor values in "real-time" if that would help.

Next Steps

Areas of the problem/possible causes.

Ignition:
-The V8s are known for blowing through coil packs, mine are both original. Is there a definitive test method for them?
-Plug wires. They're new, and seem to be of high quality, but might be crossfiring.

Oxygen Sensors:
-Again, original sensors but values/readings seem to be OK. Is it seriosuly worth putting in new ones?

Fuel Delivery/Injection:
-Pressure seems OK, recent fuel filter.

Evaporative Emissions:
I used to think it was an ignition problem, but in light of my recent experiances filling up with fuel I'm really thinking this could be a canister problem. The problem is worse when the tank is full, or I'm in hot weather stop and go traffic.

I'm not ready to start throwing parts into this truck - i want to solve this through diagnostics.

My problems are very similar to these guys: http://www.explorerforum.com/forums/showthread.php?t=64677&highlight=Lemoneer

Problem Description:

Here is a copy of how this problem has happened based on a conversation I had with Glacier991:

Last summer the truck ran great, I was averaging 16mpg, a light touch to the accellerator and she'd take off. I had new Autolite copper plugs in. The truck did throw the P0340 code, and I tested the camshaft posn sensor and it tested fine, the code automatically reset itself.

In october I went wheeling, and one of the guys i was with said it sounded like the engine was missing, so I put in Bosch platinums and new 8mm Autozone wires... not much change.

Around November on a trip, the CEL came on with some minor misfiring. Was a P0300, random misfire. had the code reset

Around Jan, gas miliage dropped to 10mpg.. truck got progressively slower. Been that way for a while, random misses and bucking but nothing major.

Then last week, it was a hot day, I had just filled up with gas from a high volume Sunoco station and hit the highway. Stop and go traffic, it starts running real rough, bucking, surging, uneven idle. CEL, felt like the truck weighed double and was running on 4 cylinders.Had the code pulled, P0300 and P0340

I put in a new Camshaft position sensor, and instantly the truck "Woke up" a very light touch to the pedal and it would jump, very smooth, and great gas miliage in city stop and go. It was the same tank of gas, just down to 1/2.

I thought the problem was fixed, until I go to refill the tank at 1/4, and within 10 min/3mi of the fill up the problem of extreme missing is back. Same codes thrown.

Test Day #1

This post is going to be updated throughout the day as I run tests on the truck. Any Ideas? Any tests, data values you would like to see?

Test #1: 12:00pm Evaporative Emissions System
Ambient Air temperature: 65 degrees
Gas Tank: 79% (Via OBD2)
Procedure Preformed: Drove 10min/5miles with gas cap removed.
Results: Truck has slightly better preformance. CEL did NOT come on.
Fuel Tank pressure: around 0.0 in/HG (OBD2)

Test #2: 12:15pm Evaporative Emissions System
Ambient Air temperature: 65 degrees
Gas Tank: 79% (Via OBD2)
Procedure Preformed: Drove 5min/1 mile with gas cap on.
Results: Tuck's performance is almost as expected.
Fuel Tank Pressure: around -3 in/HG (OBD 2)

Basically the truck was preforming well this morning. Maybe it was due to the 80% fill up, maybe it was the temperature. I'm going to put this test on hold, and wait for it to be warmer. I'll top off the tank close to home, and with the Laptop attached. Question: With the gas cap removed, why was the CEL not triggered?

Test #3: 2:00pm Drive Cycle
Ambient Air Temp: 70 degrees
Gas Tank: 70% (This thing is SUCKING gas!)
While driving around, the performance was awesome. Back to the way it should be. I did nothing!!

Test #4: 3:30pm Drice Cycle, Fill up
Ambient Air Temp: 70 degrees

Filled up the tank with gas from another station, and low and behold, within about 3 miles and 15 min the truck started acting up. Sluggish, got my P0300 and P0340 codes, and shaking accompanied by low rpms while idling in gear.

Test #5: MAF Cleaning/PCM Reset
Still nagging at me was the high "calculated load" value, so I disassembled the MAF Sensor and found that the wires were visibly dirty. Cleaned them using Denatured Alcohol, cleaned the MAF housing with brake cleaner as well. Unplugged the battery, we'll see what happens tonight.

Took it for a 30 min drive, with the scanner hooked up. Whoa.
Ambient Air Temp: 60 degrees
Fuel Level:

After having had the battery disconnected for several hours, I completed the following drive cycle, all in "D": Idle-25mph-stop for about 3 min. Acceleration to 35mph, 3 min, Highway 50mph for 15 min, decel to turn around, accel to 50mph highway for 15 min, 25mph back to the house. Throughut the truck was sluggish and bucked some. Onramps and merges were difficult.

Here's what the scanner told me (for most of the highway trip, 1500rpm, 55mph):
Short Term Trim1: -23.5
Long Term Trim1: 0.0 (This ended up jumping to -25 after I got off the highway)
Short Term Trim2: -1.6
Long Term Trim2: -25 (Went to -4.7 after I got off the highway.)
Spark Advance at Idle: 18.5deg
Load at Idle: 34.5%

Smelled something aweful! Mostly like fuel.

When I got out of the truck, there was a pronounced metallic clinging, almost like someone crumpling tinfoil from the 2 rear cats (the truck has 4, two per bank). I measured temps for the heck of it with the truck off, and both F/R of the rear cat was 376 degrees F, while the Front of the forward cat was 197 degrees, and the Rear was 240 Degrees. Could this mean bat cats? Why the rear ones and not the front?

CODES: YAY- new ones!!! Since it was only one drive cycle, they did not trigger the CEL, but were pulled from memory.
P0340: Camshaft Position Sensor
P0300: Random Misfire
P0172: System Too Rich, Bank No. 1
P0175: System Too Rich, Bank No. 2
P1130: Lack Of Upstream HO2S Switch, Adaptive Fuel Limit, Bank No. 1
P1132: Lack Of Upstream HO2S Switch, Sensor Indicates Rich, Bank No. 1

These codes pretty much confirm the Rich Condition and the fuel trims at -25

Cylinder Misfire Counts:
Bank 1 (Pass Side): [Am I correct here in relating banks to cylinders?]
Cyl 1: 97
Cyl 2: 16294
Cyl 3: 17
Cyl 4: 5
Bank 2 (Drivers side):
Cyl 5: 2
Cyl 6: 28
Cyl 7: 5
Cyl 8: 0

OK... Now for some diagnostics.

For reference:
Passenger side coil: 2,4,7,8
Driver's Side coil: 1,3,5,6

Not sure if it invalidates these results, but the drive cycle was completed with the gas cap REMOVED. The EVAP system did register that it's test cycle was completed, however, and no EVAP related codes were thrown.

The evap emissions test is a drive cycle test. In other words it is not continuously monitored. The computer will, in a drive cycle (or maybe every other drive cycle) set up a test of the system and watch for unexpected results. In other words, you just didn't drive it long enough.

Glacier991 said:

The evap emissions test is a drive cycle test. In other words it is not continuously monitored. The computer will, in a drive cycle (or maybe every other drive cycle) set up a test of the system and watch for unexpected results. In other words, you just didn't drive it long enough.

Click to expand...

OK. That explains the lack of a CEL. However, the gas cap on and off doesn't seem to have an effect, since after I filled up the truck, it started running poorly again. I treid driving with the cap on and off, no luck. I can run a test mode from my OBD2 Scanner, and every time I get failures on:
EVAPRISEL, and CATRAT. What does this mean?

I've been trying to quanitfy the change in driveability beyond the "seat-o-the-pants o-meter" and here's what I've noticed:
1) When its running normal, I can get up to speed with traffic by about 2100rpm. The truck is very strong throughout 1200-2500rpm, no need to go higher. Accel pedal is rarley pushed beyond 3/4.
2) When "Crippled" I will routinely have to floor the pedal for it to slowly climb to 3000 rpm. On the highway, merges will take a very long time, even with the accellerator floored. The downshift helps, but not by much.

Been doing some research/homework on OBD2:
OBD2 Basics: http://www.babcox.com/editorial/tr/tr60244.htm
Great site: http://www.obdiicsu.com


Std. Ford Drive Cycle: http://www.obdii.com/drivecycleford.html

Ford Non-Enhanced (1996-2001) Evaorative Drive Cycle: http://www.obdiicsu.com/Docs/DriveTraces/FordEvapDriveTrace2.html

are the values on your o2 sensors consistant? also how about the iac my explorer had a partialy stuck iac and did the same thing i tapped on mine lightly and instant change in idle and performance also you have to consider the possibility of poor gas as opec is not in production right now and alot of companys are watering their fuel

after more reading it sounds alot like a o2 problem they give input to just about every system on the vehicle my vote is on o2

cjbarron5 said:

are the values on your o2 sensors consistant? also how about the iac my explorer had a partialy stuck iac and did the same thing i tapped on mine lightly and instant change in idle and performance also you have to consider the possibility of poor gas as opec is not in production right now and alot of companys are watering their fuel

Click to expand...

Thanks for the Input!

The jury is out on the O2 sensors, but I think I am going to replace them. They appear to be swinging between 0.01 and 0.7 volts, and *sometimes* centering on the ideal 0.45 volts. The OBD2 tests seem to think they are still functional. I presume they are original, and if so, at 116,000mi are due for replacement. I have held off since the voltages do seem OK. They could be responding late, or poorly.

Interesting tidbit: The truck does idle smooth when the PCM is in open loop mode, not using the O2 data.

As for bad gas? It's been on my mind but I've discounted that fact. The problem happens when the tank is filled from different stations, then sometimes (lately) clears up as the tank empties. Also, my Dad fills up his Isuzu Trooper and my Mom's Acura RL from these same stations and does not have a problem with either car.

I'm now also exploring the probability that the MAS is to blame for some of these troubles. It would explain the high "calculated load" values, the rich conidition, the poor fuel economy, and it is also reporting that there is airflow when the truck is stationary, and off!

V8BoatBuilder said:

I've had a missing/lack of power/CEL problem for a little bit, recently its become much more troublesome.

Truck
Base: 1997 Mercury Mountaineer 5.0 302 V8. 4R70W Automatic.
Mods: see link below for Elite Registry

Symptoms Summary:
- The computer will routinely generate codes P0300 - Random Misfire and P0340 - Camshaft Position Sensor Failure.
-The truck feels sluggish, like its towing a heavy trailer (i looked... its not) or the breaks are dragging (they're not), or its not running on all cylinders.
-The truck smells like its running very rich. When I back up, It smells like latex paint or turpentine. I've been filling up at several different gas stations, all high volume and no difference in smell. The truck has been averaging about 10 miles per gallon in mixed driving, it used to get around 13.
- There is often a surging or bucking. Sometimes it is minor, other times VERY pronounced. This is usually when the CEL is set off.
-The last two times I filled up with fuel from the same high volume Sunoco station, about 15min/3miles later the CEL will be thrown and the truck will run like crap. It feels like its running on half its cylinders, won't idle, shakes, very slow, etc. There was a very strong smell of gas in the cab as well. I'm thinking canister purge system? Both days it was around 75 degrees out, and I was in stop/go traffic.

Parts Installed in effort to correct problem:
- I have installed a new Camshaft Position sensor, but the P0340 continues to be thrown.
- It has Bosch platinum plugs, and Autozone 8mm Silicon wires within the past 2000 miles.
(snip)

Click to expand...

About three months ago, my '97 Mountaineer was behaving like this, with the only exception being the code reader noting a cylinder 1 misfire, not a random one.

Like you, I first replaced the plugs, which seemed to cure the problem for a few hours. Before long, though, it once again felt as though I was dragging an anchor. The OBD-II codes were the same, so I installed new plug wires. Again, it smoothed out a bit - then quickly reverted to its bad behavior.

Finally, I changed out the coil packs - no more trouble. If you're still having the same smell/surging/low power problems, try replacing those coil packs before messing with the Camshaft Position Indicator.

New Findings!

Well in light of the road test last night, I pulled out all of the spark plugs.

Found some VERY interesting results.

Bank #1 (Pass Side):
Cylinder #1: Plug looks fine, but is soaked in fuel. Strong gas smell.
Cylinder #2: Plug is completely fouled black. Wet, strong gas smell.
Cylinder #3: Plug semi-fouled, light gray. Dry, but gas smell.
Cylinder #4: Plug is black and fouled, dry.

Bank #2:
Cyl 5-8: All plugs are perfect, electrodes are either bare metal or have a fine silver petina on them. Towers are all white. Dry, no smell.

Went to do a compression test. Unplugged coils, disabled fuel pump, removed all spark plugs. Granted, comp tests are supposed to be done on a hot engine, but I wanted to do this Q&D.

Upon bumping the starter, gas flew out of Cylinder #2, getting the block wet. AH-HA!!

Either Cyl #2 is not firing at all, or the injector is stuck open. I need your input on what would cause one bank to be semi-perfect, and one bank to be toast. The coil packs split banks, with Cyl #2 (the highest fouled) and Cyl #8 (the least fouled) on the SAME coil pack.

I'm going to test the plug wires, and then put my Copper Autolites back into the motor along with a single new coil on the #2 Cylinder.

V8BoatBuilder said:

Well in light of the road test last night, I pulled out all of the spark plugs.

Found some VERY interesting results.

Bank #1 (Pass Side):
Cylinder #1: Plug looks fine, but is soaked in fuel. Strong gas smell.
Cylinder #2: Plug is completely fouled black. Wet, strong gas smell.
Cylinder #3: Plug semi-fouled, light gray. Dry, but gas smell.
Cylinder #4: Plug is black and fouled, dry.

Bank #2:
Cyl 5-8: All plugs are perfect, electrodes are either bare metal or have a fine silver petina on them. Towers are all white. Dry, no smell.

Went to do a compression test. Unplugged coils, disabled fuel pump, removed all spark plugs. Granted, comp tests are supposed to be done on a hot engine, but I wanted to do this Q&D.

Upon bumping the starter, gas flew out of Cylinder #2, getting the block wet. AH-HA!!

Either Cyl #2 is not firing at all, or the injector is stuck open. I need your input on what would cause one bank to be semi-perfect, and one bank to be toast. The coil packs split banks, with Cyl #2 (the highest fouled) and Cyl #8 (the least fouled) on the SAME coil pack.

I'm going to test the plug wires, and then put my Copper Autolites back into the motor along with a single new coil on the #2 Cylinder.

Click to expand...

My hunch is that replacing the coil which fires the #2 cylinder will fix the problem. Clearly that is the one with most of the trouble - and as I mentioned, in my case I was reading no other misfires except Cylinder #1 - all others were within specification (I believe a certain percentage of misfires are overlooked as "normal"). I had three cylinders firing with no problems from the same coil which was tripping the CEL for cylinder #1.

Your injector might not be stuck... but it *has* been throwing fuel into an effectively dead cylinder. You can bet that the rings are wet with gasoline; the fuel that you noticed when you bumped the starter might've come from there.

Once you get this sorted out, change the oil. The crankcase oil may have been thinned a bit by unburned fuel leaking past the rings.

Keep an eye on that other coil pack, too - Cyl. #1 may be a distant second place in the number of misfires logged, but it might continue to cause problems even if you sort out Cylinder #2. Your "Bank 1 too rich/Bank 2 too rich" trouble codes could be indicating other cylinders which are misfiring just below the ECM's threshold for throwing trouble codes, too... especially on cylinders 5-8.

Are those coil packs the originals?

always replace coil packs in pairs!!!!!!!!!!!!!! i know it is expencive but it is just like brakes you dont just change one side you change both but some people have diffrent opinions on this also just my 2 cents

I presume the coils were indeed original. I bought the truck last year with 106,000 on it, and most parts with the exception of filters were Motorcraft, and didn't appear disturbed. I do not have previous maintence records. I went out and bought a second coil pack, and I'm installing them now. I'm using the generic ones made by "Wells" from Autozone. Opinions on these packs?

Questions:
Is there a way to test the packs with a multimeter?

Also, I bought new O2s for the before-cat locations. Think its worth it putting them in now? On one hand if the current O2s are slow responding due to their age (116k mi) they may be contributing to the problem, on the other hand I don't want to foul new O2s..... what would you do?

Well the coil packs weren't the problem - its something a LOT larger. Took it out for the test drive today, and it still ran horribly. I was getting lots of white smoke on startup, with a tinge of blue. For the first few miles, I was getting a cloud of blue smoke from the tailpipe. Took it on a 20mile, 1 hour drive to see if the blue smoke was just from the bumping of the starter motor yesterdat and/or remnants of sea foam. No dice.

Heard some "popping" from below, possibly the cats lighting off fuel/oil? Or backfiring? I need input here.

Got similar misfire counts as before:
Bank 1:
Cyl 1: 125
Cyl 2: 10,775
Cyl 3: 208
Cyl 4: 119

Bank 2:
Cyl 5: 3
Cyl 6: 11
Cyl 7: 11
Cyl 8: 0

Codes: P0340, P1132, P0300, P0172, P0175.

New news: I got a fault on Fuel Injector #2 from the Enhanced Codes.

Compression test results:
After the 1 hour/20mile test drive I let her sit for about 15 min.

I did cyl #2 first, and got 71psi, then 100 psi, then 100psi again. Spark Plug: Completely fouled, black, wet after only 20miles.

I then did the following (all numbers psi):
Cyl #1: 147, 147 Spark Plug: OK, slightly damp
Cyl #3: 150, 170, 147 Spark Plug: OK
Cyl #4: 130, 100, 150 Spark Plug: OK

Bank #2: Driver's Side
cyl #5: 160, 160 Spark Plug: OK
cyl #6: 155, 155 Spark Plug: OK
cyl #7: 160, 150 Spark Plug: OK
cyl #8: 160, 150 Spark Plug: OK

I went and re-did cyl #2 and found:
120psi, 120psi, 150psi, 150psi.


Hrm.... Thoughts?

Excellent approach. I think you may need to next change out or at least carefully scrutinize the injectors. Then if there is no result there either, changing or swapping the ECM is the last step. PM me and I'd like to discuss my similar scenario with my 1997 XLT 5.0 that I've changed just about everything except injectors, EGR system, and PCM. My hunch is that this may be a computer glitch with ford that is developing over time.

performancenut said:

Excellent approach. I think you may need to next change out or at least carefully scrutinize the injectors. Then if there is no result there either, changing or swapping the ECM is the last step. PM me and I'd like to discuss my similar scenario with my 1997 XLT 5.0 that I've changed just about everything except injectors, EGR system, and PCM. My hunch is that this may be a computer glitch with ford that is developing over time.

Click to expand...

Dude. I bought an injector, fuel filter, and intake manifold gaskets at Autozone this evening and am going to do exactly what you suggested tomorrow morning. I'm keeping my fingers crossed. A stuck-open injector would definitley cause most of my problems.

I also purchased an injector test light - and am going to start there, along with a third scruitny for spark at #2.

However, there is the possibility that it is leaking oil into the cylinder as well via a sticking valve. I have not discounted the head gasket either. I'm keeping my fingers crossed.

Also, feel free to talk about your truck here if the problem is similar rather than over PMs, we'll both getting better input and be closer to solving the problem with the exchange of data.

V8BoatBuilder said:

I presume the coils were indeed original. I bought the truck last year with 106,000 on it, and most parts with the exception of filters were Motorcraft, and didn't appear disturbed. I do not have previous maintence records. I went out and bought a second coil pack, and I'm installing them now. I'm using the generic ones made by "Wells" from Autozone. Opinions on these packs?

Questions:
Is there a way to test the packs with a multimeter?

Click to expand...

Yes, there is a reasonably good method given in the Haynes manual. I had a intermittent misfire due to the secondary resistance being too high.

See this thread: Coil Pack Testing

A leaking injector wouldn't give low compression numbers. I suspect you have a mechanical problem like a blown head gasket, cracked head, burned valve, etc. Is your coolant level dropping? Are you sure the wet plug is caused by gas? It could be coolant.