Hey Every one, thanks in advance for the threads that are already out there concerning this sort of thing.

About 3mths ago my auto 96 Explorer v6 4.0L, kicked on the CEL and gave me the codes P0171 and P0174, like an idiot I immediatly replaced my o2 sensors, before I knew much of anything about the codes, I've also since then replaced my MAF, replaced the O-rings on the injecters and replaced the air intake manifold gasket, as well as my EGR valve. I can't find any Vacuum leaks.

When the truck is first started, it will struggle up to a higher than normal rpm, then drop down and stall. By giving it a great deal of gas I can usually get it going. The problem after that is when the truck is turned off for more than say about ten min. it won't turn over most the time, if it does it takes more gas peddle pumping to finally get going again, also at this point if I give it too much throttle when restarting, it will die, so its a game of can I start it and giving just enough throttle. After it gets going it will run fine, unless you need acceleration, which means that gassing it gets me to 25mph and 3000rpm, before it feels like the "governor" kicks in, if I force it, it will get above 3000rpm but no speed at that point. The only way to get it to higher speeds is to ease it up there...

Any suggestions? I really love this truck but its making me very angery...

 

You need to check your fuel pressure, from the symptoms it sounds like low fuel pressure. Another possibility is plugged exhaust (likely catalytic converters), but that typically doesn't set lean codes.

 

Also, is it a SOHC motor? Those were prone to intake manifold gasket/o-ring leaks. Not sure if this is what you meant by "air intake manifold" or not.

 

Intake manifold gaskets

 

The SOHC motor was first available in 1997. The OP says that it is a 1996.

 

I'm pretty sure that its the OHC, but I may be wrong, but even if I am I replaced the o- rings you're speaking of I think...

 

Unless you did a motor swap in your truck its the OHV motor. Like I said, the SOHC motor was first available in 1997.

 

Yes it sounds like the intake gaskets... rubber band-looking o-ring things. You'll notice the new ones are about twice as thick as the originals. I didn't mention that because you said you replaced the "air intake gaskets", but now I'm thinking you meant where the "butterfly" valve bolts to the intake.

Good luck.

 

I replaced the gaskets around the injectors and the air intake gaskets (the flat on similar to a head gasket, and the circular rings on the upper piece) Do these sound like what you are suggesting or is there a set that I missed... I honestly might have I didn't know anything until I started on this problem,