please help i am stuck, i have a 1992 gmc jimmy with "w" motor, up untill 2 weeks ago it ran fine, just had slit power loss and surge at mid rpm, past week it ran so mint no problems, yesterday it developed a miss at idle, not like a random missfire like a complete engine missfire very lightly, today started normal, drove around slower then i usually would very light throttle, all the sudden it started bucking, sputtering, felt like it was starved for fuel, then stalled, would turn over but wouldnt start untill it cooled, i changed the coil, egr valve, seafoamed changed tps sensor, and added dry gas because i recently got gas at a station ive never used, but the problem is still there, when it gets hot and wont start, if i put gas in the throttle body it starts, fuel pump turns on and has pressure, i am stumped, it has spark compression intake, and fuel pump is pumping fuel

could it be the regulator? spider?, icm?

please help me, ive never had a problem like this and ive been working on cars since i was 14
ive owned 5 blazers and 2 jimmys this is my first vortec so please help thank you so much

 

when its cold it idles fine, feels somewhat better cold but still hesitates and bucks and eventually shuts off, i know ive seen this thread before but ive seen people making wild suggestions like pcv valves and starter solenoids, please if you dont know what this is dont guess

 

I would say regulator is starting to go. Whats your Fuel Pressure at key ON? Should be close to 60 psi and hold that for at least 5 mins.

 

at key on its 58 psi, dropped 5 psi after 1 hour

 

You say you replaced the egr valve. That is what happened to mine. This exact problem. Fine when cool but when it was hot it would buck and chuck. Felt like It was throttling the fuel. but mine is a 95. I had a P0701 code. Map sensor. But it turned out my egr valve was actually broken at the base. Replaced it with a used one last week. Purrs like a kitten again.

 

any advice, i need that admins help but i dont want to pm him
i think his name is swartik

this is my only vehicle i have no way to get my 5 month old daughter to the doctor tommroow,
please help, i think that the problem is the injector isnt pulsing
could it be the relay,
it will idle all day long but if you floor it in nuetral it will hesitate and start sputtering at 4000 rpms, if you put it in drive it bucks and eventually dies then wont start back up for like 15 minutes
but if i poor gas in
the throttle body it will start for 2 seconds and die
please help this is fuel related issue, i dont want to throw parts at the problem, everyone else i see with the exact same problem threw so many parts at it that they have no idea which one actually fixed it

 

have you tried the fuel pump relay? checked vacuum lines?

 

Did you leave the fuel pressure gauge on while you were revving it to 4000? Whats the readings change to when it misfires.

It sure sounds like an EGR problem to me too.

 

the fuel injection harness wasnt making contact, took it out and fixed it, upper plenum gasket was leaking too, changed regulator,inside of dist cap had green and black deposits on contacts, pass rear spark plug boot soaked in tranny fluid from overflow leaking when transfer was overflowing into tranny
the previous owner had champion spark plugs in it lol put in ac delcos runs mint now still hesitating a lil bit think the spider needs to be changed