Explorer Bucks really bad under acceleration

[Rhett]

Well, if your plugs are sooty and dark, sometimes that means the engine is running rich. A bad fuel pressure regulator can cause the engine to run rich...

 

[grn92conv]

Well i got the pcm to work obviously. So thats not the problem.

Its not the plugs or wires because they are all brand new.
Im getting a 998 then a 157 which means that my maf is pretty much junk. Im going to try cleaning it again in the morning if it doesnt work ill get a new one from a junkyard and see what happens from there.

Did you ever find if the problem was for sure the MAF sensor? The reason I ask, is I have almost the exact same problem..
Same codes, but the symptoms are a little different. Mine's running pig rich, leaving black places on the ground (from the exhaust pipe) when idleing still for a minute. It does have surge and weak idle, but this is only when sitting still at idle. It blows some serious black smoke under heavy acceleration..

Any one?

 

[Rhett]

Did you ever find if the problem was for sure the MAF sensor? The reason I ask, is I have almost the exact same problem..
Same codes, but the symptoms are a little different. Mine's running pig rich, leaving black places on the ground (from the exhaust pipe) when idleing still for a minute. It does have surge and weak idle, but this is only when sitting still at idle. It blows some serious black smoke under heavy acceleration..

Any one?

Your problem sounds like the fuel pressure regulator. At least that would be my first assumption, based on what you've posted. Pull the vac tube on it and see if there is any raw fuel in it.

 

[grn92conv]

Your problem sounds like the fuel pressure regulator. At least that would be my first assumption, based on what you've posted. Pull the vac tube on it and see if there is any raw fuel in it.

Hi, Rhett. Thanks for your post.
I too was thinking the regulator was the problem. So I checked the fuel pressure at the shrader valve and had a steady 30psi

What I've done so far is. Check the fuel pressure, gave complete tune-up with new wires as well. Cleaned the MAF sensor.
I was thinking the ECM itself was at fault, until finding this thread. Now I'm thinking MAF sensor????? but you guys are more familiar with explorers, so >???

 

[taylor0987]

Does your truck have EGR? If it does, try disconnecting the egr valve vacuum line temporarily. If the bucking goes away then it's probably a problem with the DPFE.

 

[grn92conv]

Did you ever find if the problem was for sure the MAF sensor? The reason I ask, is I have almost the exact same problem..
Same codes, but the symptoms are a little different. Mine's running pig rich, leaving black places on the ground (from the exhaust pipe) when idleing still for a minute. It does have surge and weak idle, but this is only when sitting still at idle. It blows some serious black smoke under heavy acceleration..

Any one?

For a point of reference, the fix for my problem above was a new MAF sensor.

Thanks explorerforum

 

[Turdle]

Sometimes,( actually quite often) a fouled plug cannot be brought back to life. Splitfire comes to mind
once they foul, they are no good.( carbon tracking)