FasTimeSS

iTrader: (47)

I am having issues with my 2002 camaro 3.8l with 161,xxx miles, it is miss firing only at idle. I have hptuners and can watch it sit there and firing several times. It doesn't seem to matter which cylinder most of the time cylinder 4 is the one miss firing. I was throwing p0300 and p0304. I recently replaced head gaskets, upper and lower intake manifold gaskets, spark plugs, wires. I switched the ICM and no difference at all. I replaced the pcv valve because there was alot of oil in the intake manifold. I also swapped injectors to rule out clogged injectors. I am at a loss here!!! It doesn't make a single miss firing under acceleration and it feels as if all power is still there. Can some give me some inside as what else I need to check so I can get this back on the road ASAP!!! Thanks

01WS6/tamu

iTrader: (37)

You try changing the position of the coil and see if the misfire moves.

FasTimeSS

iTrader: (47)

I had the ICM tested and it tested good. I have switched the coils around and nothing seems to work. I am leaning towards a vacuum leak somewhere at this point but I can not find one.

5w20

iTrader: (21)

worn cam, needs more comp.

ls1_bean

iTrader: (3)

put a 5.3 in it brosef

CRASHz427

iTrader: (14)

Not to thread jack but I'm having a similar but worse issue. Same car same mileage. So maybe someone can help resolve both our issues.

Driving the car one day and it just dies. Won't start back up. Bring it home run through all the typicals and found that once it fires the fuel psi drops off. Put in a new pump now it won't even start. Turns over freely, fires on starter fluid but run on its own. Throwing a p0300 which I knew it had a miss, and a p1516. Any thoughts?

ramairracer

iTrader: (13)

probably a leaking fuel pressure regulator, if it leaks passed the diaphram, it sucks it through a vaccum hose attached and will run that unmetered fuel.. pull that vaccum hose off and see if its leaking. Also another symptom would be having to crank it longer than normal when starting or having to cycle the key twice

FasTimeSS

iTrader: (47)

I replaced the fuel pressure regulator and no luck with that either. That was one of my thoughts too. I put a new fuel pump in the car a few months back and I am wondering if that is when it started to run shitty. I need to check fuel pressure at idle and see if it is low.

CRASHz427

iTrader: (14)

Ok. so I just walked back in the house from jacking with this car all day. Im about burn it down. Im glad I read your last post before I went to autozone to buy a new fp reg. Something has to be cutting the pump off.

Here is the scenario:
Key on 50psi
While it is turning over fp falls off quick to below 20 psi
Stop cranking key on back to 50 psi

Pulled the vacuum off the reg and no leaks.

CRASHz427

iTrader: (14)

UPDATE:

Got mine fixed!! Put a new set of plugs in it and it fired right up. Let it run for about 20 min then noticed the oil psi gauge going south. Once it hit 5 lbs the car cut off. I never payed attention to the oil psi gauge so apparently I have a bad oil pump and once it drops below a certain level it kiils the fuel to the car. That explained my fuel psi drop off at start. I had to start it again to move the car and noticed that it wouldn't start until the oil psi at cracking got above 10 lbs. So to sum it up the oil pump has been the culprit the whole time. New oil pump installed and she runs like new. Hope this help anyone in the future of chasing these gremlins.