Sputter/Stutter and Loss of Power

So the explorer developed some sort of misfiring/sputter/stuttering last night. Occurred on the highway while cruising and was pretty bad. I had to keep gassing then letting go, gassing then letting go.

This morning before work, the explorer had a constant light sputter and developed a more profound one while cruising and even accelerating. If the sputter got real bad, I could smell what smelled like weed eater gas inside the cabin. As you could also imagine, there is a loss of power. Upon googling and past knowledge I have came up with the following conclusion. Can someone help me confirm as to which is true? I can’t just throw money at a problem like I used to so I want to pinpoint it.

1)Engine is misfiring due to potential dying plug. Records show in July of ’08 I installed Champion Copper Plus plugs due to a HHO project I was doing (never completed). I read copper plugs need to be replaced once a year or 6k miles. Replace with Autolite Double Plats?

2)IAC is sticking. The stock has been replaced about 50k miles but I know the IAC in these trucks can be problematic when they get real dirty. Change it?

In the past I’ve had this problem but only once in a blue moon at a stop light. The truck would idle funny so I would put in N, rev her a bit, and the idle would return to normal. In an attempt to fix this, I replaced the EGR valve and EGR Valve position sensor but it didn’t work.

Plugs don't go bad in 6K miles. A standard copper plug should last at least 30K.
The IAC will not cause a sputter either.

Sounds like you have a misfire. The smell is raw gas being dumped into the cat. Not good.
Do check the plugs, wires and coil packs. Pull the plugs and look closely at them. They will tell you which cylinder is misfiring, if not all of them. Did you try to pull any DTC's?

Try changing plugs and swapping back to the stock maf. I would start there. Also check you plug wires around your headers for melting

Thanks guys. To My98nnj- I just read copper plugs go bad much quicker than plat/iridium which is why they cost less. A google search yeilded changing them every year or 6k miles. I will look to see if any are fouled though. I have no cats on the truck, but I never smell the gasses in the truck until now. The smell is very bad when the sputtering happens. The coil pack is fairly new so I hope that isn't the problem (about 20k old). Wires were changed when plugs were too. I will inspect this to see if they are melting.

Boominxplorer- nooo not the stock MAF! jk- but I will try this when I get home. I need to dig up the stock MAF if i can find it somewhere. Out of curiousity, what would this have to do with the sputtering? Ive had this aftermarket MAF on for about 3 years now

Update to this.

Got some codes pulled. P1151 was yanked. Ran a google search and said driver side upstream O2 sensor most likely needs to be replaced. Woohoo! Finally. SO I replace it- same thing. Sigh. On top of this I replaced all my plugs with Autolite Double Plats and cleans the MAF sensor. I'm planning on replacing the wires and passenger side upstream O2 sensor as well. There are no downstreams as these were eliminated by the tune and offroad Y. Any other ideas?

What did you gap the new plugs to?

.054 as per Ford Spec

Tomorrow yeilds a check list of things to do after an hour of searching

1. Change the fuel pump relay
2. TPS Test Procedure
3. MAF Sensor test

Will post updates. Anyone have other ideas?

Please keep posting, as mine has recently started this, but the smell isn't 2 smoke gas, its more moldy smelling.

colintrax said:

Please keep posting, as mine has recently started this, but the smell isn't 2 smoke gas, its more moldy smelling.

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I am without cats so I smell the pure unburnt fuel.

Are you experienced hesitated starts, lack of power, kind of hesitant during cruising? Did you get any codes pulled?

I got the codes pulled, the dude just said my EGR vavle was bad.
It starts up fine, also it will only have lack of power occasionally, which is scarry. I don't know if it will launch, or just kind of sputter and hit MAYBE 3k rpms before it shifts and continues sputttering.

colintrax said:

I got the codes pulled, the dude just said my EGR vavle was bad.
It starts up fine, also it will only have lack of power occasionally, which is scarry. I don't know if it will launch, or just kind of sputter and hit MAYBE 3k rpms before it shifts and continues sputttering.

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I've had the same thing. The occasional sputter while driving or rough idle at a stop. I would just mash the gas and it would disappear. I replaced my EGR valve and EGR position sensor in an attempt to fix it but it never did. Now I it's become so persistent that I must fix it

Relay is only ran when the motor isn't running.
Fuel pressure is good? Fuel pressure regulator isn't leaking into the vacum line?

Which engine & codes?

Afboy143 said:

I've had the same thing. The occasional sputter while driving or rough idle at a stop. I would just mash the gas and it would disappear. I replaced my EGR valve and EGR position sensor in an attempt to fix it but it never did. Now I it's become so persistent that I must fix it

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Do you have the SOHC or OHV V6?

Do you have any current diagnostic trouble codes?

A dirty or bad IAC valve should not cause any symptoms except at idle.

A single cylinder misfire is normally detected and reported by the PCM. Misfires due to MAF sensor, TPS, fuel pressure, camshaft and crankshaft position sensors often are not isolated and reported by the PCM.

How many miles since you replaced your fuel filter?

2000StreetRod said:

Do you have the SOHC or OHV V6?

Do you have any current diagnostic trouble codes?

A dirty or bad IAC valve should not cause any symptoms except at idle.

A single cylinder misfire is normally detected and reported by the PCM. Misfires due to MAF sensor, TPS, fuel pressure, camshaft and crankshaft position sensors often are not isolated and reported by the PCM.

How many miles since you replaced your fuel filter?

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I'm sorry. I have the 4.0 SOHC motor

The code the computer threw yesterday was P1151. Upon googling and searching, I read this is usually the precat sensor on the driver side. Replaced and still nothing.

I am going to run your MAF and TPS tests today. Fuel pressure- saw a thread you posted by a test kit from harbor freight. May stop by and see if I can pick that up.

Fuel filter has about 20k on it give or take. I should see about changing this out?

camshaft and crankshaft sensors- anyone to test these?

EricM- the only reason I said I would replace that relay is another member had a similar problem to me. It ended up being his fuel pump relay that went bad

DTCs and tests

Afboy143 said:

. . . The code the computer threw yesterday was P1151. Upon googling and searching, I read this is usually the precat sensor on the driver side. Replaced and still nothing.

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

Did P1151 come back after you replaced the O2 sensor and cleared the DTCs?

Afboy143 said:

I am going to run your MAF and TPS tests today. Fuel pressure- saw a thread you posted by a test kit from harbor freight. May stop by and see if I can pick that up.

Fuel filter has about 20k on it give or take. I should see about changing this out?

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Suggested replacement interval for fuel filter is 30,000 miles. Yours should be OK.

Afboy143 said:

camshaft and crankshaft sensors- anyone to test these? . . .

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There are some tests described in my Haynes Repair Manual that I've never tried. Try disconnecting and reconnecting the electrical connectors a couple times to clean the contacts. The crankshaft position sensor is exposed to the elements and the contacts may be dirty.

EDIT:

Well I stopped by Advance Auto parts this morning to get codes pulled again. P1151 is gone now. There are now 4 codes in the bank instead of 5.

On the initial reading, I ignored the 4 codes and concentrated on the 5th because the 4 codes, per the guy at Advance Auto, referred to the lower 2 O2 sensors. The reason I ignored these is I deleted them with the Y pipe and tune, but I untuned the truck about 6 months ago due to money is tight and premium fuel is expensive. It's been running fine like this so I ruled them out. (Untuned with rear 2 O2's deleted) The following is the 4 codes just pulled 10 mins ago

P0136 - Bank 1 sensor 2 circuit fail
P0141 - Bank 1 sensor 2 heather fail
P0156 - Bank 2 sensor 2 circuit fail
P0161 - Bank 2 sensor 2 heather fail

As you can see all refer to the downstream sensors which ive had these codes in the computer since I detuned about 6 months ago

I bought the O2 sensor for the passenger side upstream, but didn't install it yet.

Just as a side thought- Im thinking of welding in the two downstream bungs and installing those O2 sensors with simulators on them.

well for lunch I went to the truck to perform the TPS test- my harbor freight meter died! It's the same red one you got StreetRod

I backed out of my parking spot then started to go forward when the tried died. Dang! So I put it back in park, cracked it back up, then went again.

I was in the drive through of KFC as I was craving their popcorn chicken and wedges. MMMM. While listening to my motor up against the side of the drive through wall, I hear a slight ticking or knocking noise. It's ever so slight and to the same pulse as my exhaust. The truck doesn't feel as sluggish today- probably because it's hotter out but there is def still a problem there. Any ideas?

just a little update. Explorer is still running a little rough, but nothing too crazy but man is she sucking gas! oh my it's rough. This weekend she will be put under a ton of tests to see what in the world is doing all this! Power seems lacking, but the cruising and idling isnt as bad but def a huge gas sucking issue! fantastic

Check fuel pressure and the Fuel pressure regulator for leaking into the vacuum hose before you throw money at parts.Step by step is the way to go,if you smell fuel find out why,look at the plugs,are they wet or fouled?

If the fuel pressure is off it will screw up all of the other readings like O2 and such.If you think you have a spark problem buy a spark tester,looks like a spark plug with a huge gap.If the spark can jump that it's good.Take your time and eliminate the obvious, fuel and spark first.

safn1949 said:

Check fuel pressure and the Fuel pressure regulator for leaking into the vacuum hose before you throw money at parts.Step by step is the way to go,if you smell fuel find out why,look at the plugs,are they wet or fouled?

If the fuel pressure is off it will screw up all of the other readings like O2 and such.If you think you have a spark problem buy a spark tester,looks like a spark plug with a huge gap.If the spark can jump that it's good.Take your time and eliminate the obvious, fuel and spark first.

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Thanks for the tips sir! I saw you check the fuel pressure by buying a special tool on 2000HotRod's useful threads list. How do you check the fuel pressure regulator?

I just changed the plugs 2 days ago hoping this was the problem and it wasn't. Problem is still there :-/. If the fuel pressure is off, this would cause excessive fuel consumption?

and don't worry- she is getting some diagnostics done this weekend in the good ol' driveway

EDIT: Just saw this website. VERY informative

http://www.2carpros.com/dia/test_fuel_pressure.htm

Hotrod- is this the tool you used?
http://www.harborfreight.com/fuel-injection-pump-tester-92699.html