motor problems with my 93

[tmark88]

Im having a hard time diagnosing an engine problem.

Here goes: Starting and driving/running my explorer at any temperature, time, condition she runs perfect...absolutely no problems. But after I have FULLY warmed the engine and shut it off for more than 10 minutes, (the duration of going to the store for a few things or time its off while getting gas) and come back out to start it....it will start up but then immediatly drop down to 200 to 300 rpm missing and surging and almost dieng and sometimes doing so.

To cure this condition I can rev the motor to 1500 to 2000 for about 15 seconds and the missing seems to slowly disapate going from (theory) 3 or 4 cylinders to 5 then 6 and finally smoothing out.

After suspecting a fuel system problem I began checking a few components. Get this......when the scenario is right and the motor has its problem I will pull the vacuum line from the fuel pressure regulator the motor will INSTANTLY smooth out and run at perfect idle.
I replaced the regulator today and it didnt help.

Does anyone know whats going on?

Thanks, Mark

 

[Jason_25]

Sounds to me like your fuel pressure regulator has gone bad. It's pretty easy to change and it's about 90 bucks I think.

 

[mrboyle]

It sounds like your X is getting to much fuel at idle. My first step would have been the FPR, but you already changed it and had no luck. The next step I'd take is to look into weither the idle air control motor (IAC) is working.

P.S. Have you checked the air filter?

 

[jimbo74]

sounds like FPR(already ruled out i think) iac, maf, o2s or fuel filter....my o2s were bad and that made my car all funky when it was warm and it did the same thing...it even stalled when i hit the brakes at idle