Running rough so I'm chasing OBD codes but getting lost

[Lenair]

I have a 1998 Explorer XLT, 4X4 that has started having some problems. It idles rough, hesitates, and almost dies when coming to a stop. The problem seems to be worst when it’s cold but it’s only marginally better when it’s warm.

Here are the OBD Codes and the timeline:

P1151: Fuel & Air Metering – Occurred back in August on the way back home after four wheeling. Checked to see if O2 sensor was physically damaged but it appeared fine. Erased OBD trouble code.

P1151: Fuel & Air Metering – A month or so later the Check Engine Light came on again. It went off the next day and would intermittently come on over the next month.

P0305: Cylinder 5 Misfire – In October the truck began to hesitate and had a rough idle. I pulled the codes and P1151 was now joined by P0505. I changed the plugs and wires then reset the code. The truck was running like a million bucks!

P1151: Fuel & Air Metering – In mid December P1151 was back again but just like before it would stay on for a while and then go off for a while but the truck ran fine. At this point I was pricing O2 sensors thinking I might need a new one.

P0306: Cylinder 6 Misfire – Last week I was driving to work when the CEL began to flash and the truck started hesitating again. I drove home that way and checked the codes the next morning which showed P0306. I removed the plug and inspected it. It was covered in oil. Since I had a new plug in the garage I went ahead and put it in rather than clean the old one. I reset the codes and the truck was fine again but I was worried.

P0303: Cylinder 3 Misfire – Yesterday on the way to work the truck began to hesitate again and the CEL flashed. I didn’t have my OBDII scanner but figured it might be that plug on the 6th cylinder again. I removed the plug but it looked normal so I headed home.

P0153: O2 Sensor CKT Slow (Bank 2 Sensor 1) – The truck sputtered and bucked the whole way home. Once there I pulled the codes and got P0303 mentioned above and P0153.

P0303: Cylinder 3 Misfire – This morning I removed the plug from the 3rd cylinder thinking I would have to clean it but it looked normal. I reset the codes and started for work but didn’t go far before P0303 was back; however, P0153 did not return.

P1151: Fuel & Air Metering – It’s still with me.

So here I am at work with my truck in the garage, my OBDII scanner in the glovebox, almost 60 miles to drive to get home, and very little idea of what to do next.

Any thoughts?

 

[reserved50]

open up mass air meter and clean the delicate wires with some carb cleaner spray?

 

[Lenair]

Here's an update...

I really didn't feel like messing with the truck after a long day at work so I tried to cheat by disconnecting the MAF. I won't do that again. Is it just me or does the tranny read the MAF? Not only did I have all of the old problems but up shifts and down shifts were clunky. I ended up stopping and reconnecting the MAF but not before spraying some Gumout thru the tube where the MAF comes thru. Here are the results:

When the MAF was diconnecting there was no OBD code (although I only drove about 5 miles).
Once the MAF was reconnected the idle seemed not as rough but still a ~250rpm swing.
Within the first 1/2 mile I got the first code which was P0303.
Shortly afterwards P1151 reared it's ugly head again.
BUT... I got a new one this time. It was P0102: MAF Circuit Low Input.

I'll try to actaully take the MAF sensor off and clean it next time. Until then I'm still open to hearing suggestions.

 

[reserved50]

dirt stuck at the back of the O2 sensor where the wires enter(since you mention it acted up after offroading), if the tiny hole back theres plugged it'll take wrong samples, if you have a code scanner, not a reader you can read live data and see what the O2s reading and how fast its switching. If the O2 looks plugged up with dirt might as well change it out if you have no way to check the operation if everything else fails(or run it disconnected/open loop to see if it runs better).

 

[Ray-Ray]

Just for everyone's information........I had a P0303 code and it was driving me crazy could not figure it out checked wires and plugs and did not see anything . Pulled #3 plug again and found it had a hair line crack on the electrode porcelin replaced the plug runs like a top now . Hope this helps

Ray-Ray

 

[2000StreetRod]

MAF sensor is essential

What engine do you have?

The PCM monitors the MAF sensor output voltage. When you disconnected it the PCM read the output voltage as 0 volts and set a DTC for out of range (low) sensor ouput. I believe the PCM reverts to open loop with no MAF sensor. In open loop the torque converter will not lock. Without a MAF sensor the PCM cannot determine engine load so it doesn't know when to shift gears. If you cleaned the MAF sensor with anything other than electronic equipment cleaning aerosol or MAF sensor cleaner you need to clean it again with the right spray.

P1151 Lack of Upstream Heated Oxygen Sensor Switch - Sensor Indicates Lean - Bank No. 2

Bank 2 is the driver side. It looks like you're getting misfires on both banks.

I suggest that you clean the MAF sensor and then perform the MAF Sensor Test Procedure

After that I suggest that you change the fuel filter if it hasn't been changed in the last 30,000 miles.
Why change fuel filter?

If you're still having problems after that I suggest that you perform the TPS Test Procedure

 

[mccoyxx]

Did you get it fixed, I am having almost identical codes as well.

Hello everyone .. I have a 96 Sport with a 4.0 and its running terrible and popping 4 codes. I am also only getting roughly 11 mpg !! Here are the codes PO153 ( O2 sensor CKT slow response bank 1 sensor 2) PO304 cyl. 4 misfire PO305 cyl. 5 misfire and P1151 manufacturer control fuel air metering. Also when i park the front on an uphill grade and let it sit it starts fine, but if I park the front end on a downhill grade it is very hard to get started back. I did take apart the throttle body & clean it and saw that it did have a small puddle of gas in the rear of the upper intake. Thank you for taking the time to try to help me in advance ... RSM

 

[mccoyxx]

Oh yes !! heres some details.

I ran some sea foam through the block in my oil and in my gas to help clean the injectors. I have replaced the air filter, plugs (autolite platinums properly gapped) new PRO wires like I believe a $65 set. , a dif. MAF sensor, a maf pressure sensor, cleaned the throttle body, checked vacuum lines. I have had it read on 3 dif. scanners 2 snap ons and an actron 9175. I have taken it to 3 mechanics and they all tell me different things ranging from burned valves, catalytic converter stopped up and some other highly unlikely things. Please help !!

 

[33exploder]

poor fuel mileage,maf voltage too high too low, tps issues, o2 codes fpr troubles??? had it all, tested everyone of them, replaced both o2 sensors, tps and cleaned the maf. nothing fixed it. i know the ground wires are great because i replaced too many of them for nought. almost forgot i replaced the ecm under the kick board too. my ex still ran bad. i pulled out the wireing diagrams when through it. and found that the tps, the maf sensor Ref (5 volts) is in series (in line) with fuel pump relay(when was testing everything i did the old touch test on relays early on this rabbit hunt and made mental note that fuel pump relay was warmer than the others) ahhah! i changed the relay and fixed all the issues.

the maf &tps are in series with the fuel pump relay. in the relay are two cercuits 1.fuel pump switch 2. the electro magnetic actuator [ema]. #2 is the part that is in series with the maf & the tps. if the ema inside the is relay starts to overheat it will effect the Ref voltage. heat causes resistance, resistance causes voltage drop, voltage drop causes issues :biggthump

CHANGE THE FUEL PUMP RELAY $15-$25

 

[33exploder]

Swap the fuel pump relay with any other relay in the power dist. Block under the hood

 

[mccoyxx]

Thank you for your time ... will give it a try tom. !! keep your fingers crossed for me !!

 

[mccoyxx]

Update , I had it checked at a garage and they said they believed my catalytic converter being clogged to be the root of the problem. So here I am 4 hours and $112 later and it didn't help at all, if anything it runs more roughly than it did. Now instead of 4 codes mentioned earlier its showing 7 !! I also put a new fuel filter. codes now are as listed P0153 - O2 sensor CKT slow response bank 2 sensor 1 , P0401 EGR flow insufficient, P1151 manufacturer control fuel air metering , P1152 manufacturer control fuel air metering, P0304 P0305 and P0306 cylinders 4,5 and 6 misfire detected. Also my battery light kicked on earlier and I thought my alternator had went out, but I turned the Ex off and restarted it and the light went out. Any suggestions ??