stuttering when gased

[geracarreon]

i own a 98 explorer xlt v6 4.0l 182k miles. The problem started with a misfire here and there and loss of power but it still got up and went and check engine light went on. one morning i tried to start it and had to crank it 4 maybe 5 times and its been like this every time i try to start it. once it starts it idles very low maybe 600 rpm and when i give it gas it tries to die. when driven it hardly moves, you could floor it and it would go 20mph tops and slowly increase speed, also stutters when given gas unless you press the pedal very slowly. also hear pops from intake like misfires.

i took it to auto-zone for a diagnostic read and they told me i had a few codes . i replaced everything that it said. one injector , coil pack, new ngk plugs, and new spark plug wires, fuel filter, and fuel pressure regulator. once all that was installed there was no difference and the check engine light remained on. so i had the idea it might be the MAF even though it was not throwing a code for it. i changed the MAF and it did turn the check engine light off but no change in performance.

any ideas on what it might be the cause? maybe internal problem? i dont hear knocking. fuel pump works . at times when warmed up in park it can be reved high no problem, but then it just goes back to stuttering and in drive it has no get up and go. it barely moves

 

[iwannabamedic]

Possible a valve is burnt, try doing a compression check

 

[2000StreetRod]

test the TPS

TPS Test Procedure

Other possibilities with no diagnostic trouble code: restricted exhaust flow, bad camshaft position sensor, bad crankshaft position sensor, clogged air filter

 

[ranger7ltr]

What was your fuel mileage right before this started?

I ask because I had a car that did this and the problem turned out to be a clogged catalytic convertor...I had to hold the throttle almost wide open just to start the engine and when it did start I could only get maybe 600 rpm out of it...When the engine is running and in park or neutral, can you rev the engine like normal? Or does the engine still labor just to rev up with no load on it?

I don't know if your truck is configured like mine but I have a pair of convertors in the headpipe off of each manifold behind the o2 sensors...

If the fuel mileage tanked it is possible that excess fuel helped to melt the elements inside the convetor and you now have a restriction on the exhaust side...

Unfortunately you would have to drop the headpipe from the manifolds and the flange to test that theory if your headpipe has convertors in it like mine...If you have no convertors, drop the pipe at the flange and see if starting and revving the engine suddenly gets easier...

EDIT...I should really learn to read the entire article..."at times when warmed up in park it can be reved high no problem, but then it just goes back to stuttering and in drive it has no get up and go. it barely moves"

This DOES NOT sound like an exhaust problem...Can you get the truck to a transmission shop so they can read any tranny codes? This sounds like the tranny is not starting in first gear...or that the tranny is trying to run a higher gear or the convertor clutch is not releasing loading the engine...

If the shifter is in any other position besides drive does driving get any better? What about reverse?

 

[MBeaston]

sounds like sugar in your fuel to me my 5.0 explorer done the exact same thing when ex wife got divorce papers

 

[ranger7ltr]

Ouch...

sounds like sugar in your fuel to me my 5.0 explorer done the exact same thing when ex wife got divorce papers

 

[MBeaston]

lol tell me about it

 

[regorsmith]

I had the same problem.
It was the exhaust gas differential pressure switch on mine.
Little black box on the drivers side of the engine with two tubes that connect to the exhaust feed to the EGR.
The sensor was giving the wrong signals to the EGR vacuum control valve and the EGR wasn't functioning at all.
Changed the sensor and it was perfect.
Took ten minutes to change.
$40 fix...

 

[drdoom]

Weak fuel pump perhaps?