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Ok, I just recently did some upgrades to my 98 camaro z28 and I'm having problems with it running. First of all the motor is a 2004 lq9 stock short block, with ported ls1 heads, polluter cam, ls6 intake, LTs, 255lph fuel pump, 42lb injectors, ls2 maf, bbk fuel rail, etc.... most of the bolt-ons. At first it wouldn't even stay running with out having my foot on the gas, then I had frost tune it, now it will idle but still not smoothly as it should, idle is at like 1500rpm, and if I try to rev it, it Hesitates, gasps and sputters then it gets the rpms up. The o2s were new when I started the build about 3 months old, same for the spark plugs and the car has just been started to idle, no drivng, but I did have them open headers while the car sat outside, could that ruin them? Also it is running very rich like burn your eyes, make you cough rich, and it smoke from it looks like the headers in the engine bay, no smoke out of the tail pipes, I check for vacuum leaks. Is this just a tuning problem? Electrical? or something else? I what to get it dyno tuned but I don't what to take it all the way to the tuner and they tell me I have a mechanical problem and they cant tune it....Does anybody have any ideas on what the problem may be?
Yes sir, I was emailing him back an forward while he had my pcm. I just want to make sure its not one of my sensors (o2s, iac, maf etc...) before I take it to the dyno. It backs fires sometimes when I rev it. I don't want to keep running it and hurt it.
242/244 on a 114 will never idle smooth with a mail order tune . . . it's a donkey dick cam and it'll probably never idle smooth anyway lol 1500rpm seems about right for that cam size and keeping the engine running. Have the tune double checked and go from there.
Yea shouldn't have said smoothly lol, but the the idle is rough, engine shakes and rpms go up and down. But I plan to change all the sensors before I take it to the dyno, and will try unplugging the o2s, I will try to post a video of it running.
Yea shouldn't have said smoothly lol, but the the idle is rough, engine shakes and rpms go up and down. But I plan to change all the sensors before I take it to the dyno, and will try unplugging the o2s, I will try to post a video of it running.
If the rpm's go up and down that is most likely a vacuum leak.
Update, I pulled the intake off to check the gasket and other hoses, and decided to pull the plugs and they all are black at the tip confirming my running rich suspicion. My question is could I had fouled them out when I first started my car without any tune? Before frost tuned it I had to keep my foot on the gas to keep it running but, I probably only ran it a few minutes like that, could they foul out that quickly?
I would try and do the 02's again for sure because I have recently had a similar issue and i installed new 02's and they were no good. Try and swap them out and check out your maf would be my first two unless you have a speed density tune
Thanks for all the replies, I used a smoke test to chase down a vacuum leak. A hose on the passenger side by the pcm has came a loose and I can't figure out what it hooks to, does anyone know what this hose plugs to?
You can see it at the top here. I had to replace my hose from the intake to the check valve so that is the larger rubber line you see going to the top of the check valve.
02-05-2017, 07:33 PM
Serious problem with 98 z28!!! 
