2.5 running issue

sablowme · July 3, 2013

ok guys been a while since on this forum and realize this one on sdimes dont move much but ill post this her and see if anyone can help me out.

92 s10 2.5a auto.

issue: random stumbling at idle...once vehicle is moving you would have to pull off the gas pedal and smash back into it to regain power.. seems to be idling up and down as if its trying to add fuel to make up for something. This is very intermittent comes and goes.

parts replaced: coil, plugs, wires, cap, rotor, random vacuum lines, egr delete, cts,fuel pump, fuel filter, air cleaner..along with little breather in the cleaner, cleaned throttle body (700 series), cleaned battery terminals, all grounds cleaned.

as you can see ive done some major work to this and beating my head against the wall as to why i cant find this. I have had alot of iron dukes but never had a "a" motor duke. this one is a tad different but im sure im chasing a electrical or vacuum leak somewhere. anyone else ran into this? im really close when truck runs good it runs great but had to get rid of this stumble... i got no codes from ecu btw

sablowme · September 4, 2013

well as a update i have done some major changes here, i know this part of the forum dosent move much but hoping someone can help me here before i unload this thing , i actually like this truck just having some issues .

so i cleaned the tbi unit (700 series) it was all gummed up and figured that was the cause of a possible vacume leak. Nope ...replaced numerous vacume lines put new ends on the vacume lines. Put the truck in the air ..no converter to have a issue with. Then i started thinking intake egr..ect so since i have to have all the stuff around the head off i sent the head out to get "tanked" and "shaved" head came back tested good nothing wrong.

replaced all the gaskets during this....change the oil..then started her up...started right up..now i got a lifter tap or something but other then that still have the "idle surge". im at a total loss!!! No idea whats going with this thing. i litterly have replaced all the parts on this thing minus pcm,iat, instrument wiriing and related.

anyone have one of these....remember GM only made the "A" motor for a few years like 90-93 i beleve and an 4 banger auto is even harder to find. i may be out of luck..lol thanks for reading.