95 3.4 v6 sputtering/running rough
 

hi. new to these forums. ive been having this issue with my car now for the past month or so, when i first start it up, it runs perfect, just like it should. however once i drive it for about a half mile or so, the motor starts running like absolute garbage, it seems like a misfire. and it sputters and cuts out while driving, and idles extremely rough. sometimes it will randomly start spitting large amounts of smoke out of the exhaust that absolutely reeks like fuel. the issue is very intermittent, and sometimes will go away if the car is just sitting there idling, but then once ya drive it a bit it comes right back. between my mechanic and i were both ready to beat our heads against a wall because we cant figure it out. we initially thought it was injectors, so i had those replaced. the casing on one was completely split. no change after the new injectors. my mechanic realised cylinder 5 was getting constant open signal, so we replaced the pcm thinking the split injector may have shorted it out. he also went ahead and replaced both o2 sensors, spark plug wires, and spark plugs. it was good for about a day, but now the issue is back. it hasnt thrown a single code through this whole time and im getting very frustrated. and tips and or imput is appreciated

sounds like its doing it when it goes into closed loop. does it run ok for a short time after you shut it off and restart after a moment? should be in open loop for a short time even if its at operating temp. a bad fuel pump would still be heated and should be faultering even after a short time to cool. older or failing pump can be unhappy once heated up and fail, wont throw a code either.

When the issue first started, it would go away if I shut it off then restarted it. Now it sometimes will but seems more consistent. It appears my fuel pump has been replaced before because there's a Nice hole cut in my floor board right above the pump. However I don't know when it was done and I'm at nearly 180k. Is there a sure fire way to test the pump? It's the only component in the fueling system that hasn't been either tested and or replaced. I also just installed new coils last night and has the ignition control module tested. No change.

test your fuel pressure. should be able to borrow a fuel pressure gauge at the parts store. download a factory shop/service manual if you havent already. brb

go here and download manual. click your year. https://www.mediafire.com/?40mfgeoe4ctti