Question99 pontiac grand prix gt non supercharged 3.8l engine
ok here goes, we have replaced fuel filter,fuel pump, fuel relay,air filter, trans fluid/filter,oil change,spark plugs, spark plug wires, coil packs, crank position sensor, camshaft position sensor, radiator, serpentine belt, and battery. i have had the ignition control module tested and it was good. At first it would run approx 15 mins, then hesitate, kinda jump/kick , rpm dropped and sometimes it would catch itself and keep running but would chug n hesitate, then die. restart it, sometimes other times it wouldnt restart for a few mins. usually u can be just sitting idle at a red light, it will silently die, but will restart. once it read after stalling, no fire, so hence changing the cps and cmps. at times it appears putting gas in it, does make its symptoms worse. it appears while accelerating it "cuts out" and trys to stall, other times it does it while idle or driving slow, but will stall at any speed. the abs light and trac off light are luminated. there has never been a check engine light on. i have had it tested with odbc testers multiple times,no codes. also the fuel gage, was stuck at 3/4, now it moves down but will only go to 3/4 even at fuel tank. it runs fine when it runs, purrs , no misses, or rough idle.once or twice maybe it appeared to have a little rough idle or longer cranking pattern to start , otherwise no odor of fumes or fuel either, no smoke from exhaust. i did have control arm replaced, tie rod ends and wheel hub assemblies inspected, and a wire being broke to the abs sensor is the reason we believe that light is on. the a/c is connected but i do not use it as it needs a new compressor. Im perplexed , as i believe it is a sensor but why no chk eng light? i have wondered if in fuel delivery too. i think fuel pressure was tested when cps was replaced and it was fine. after replacing sensor it runs good a day or two, no stalling, then starts all over. hope you know the culprit, cause im ready to give up!
AnswerHi there.
seems like you have tried every common issue on these but the MAF sensor. was the cranks senor replaced with an original equipment part? If not I would look long and hard at that as well. have you cleaned the throttle body and the idle control motor? a can of carb cleaner or air intake system cleaner works great for cleaning them. Other thyen the 2 items Imentioned it's not more else that could be wrong with it. I'm sure it's a sensor too that instantly gives the engine control module an bad reading and it throws the fuel delivery off. On last thing I just thought of with the engine running pull the vacuum line off the fuel pressure regulator make sure ther is no raw gas in the vacum line. or try with the the engine is off and the car has sat for a while pull the line off and make sure there is no fuel in the line if there is replace the regulator. good luck :-)
