Chris May

hello ive owned this camaro iroc z for 2 years now and i just recently started tearing into it to figure out the issues it has. so my issue is that when i start it in the morning or when its cold, i get an idle that stays around 1500 rpm. the idle hunts up and down about 100 to 200 rpm. it stumbles and backfire through the intake when i give it gas. if i feather the gas i can get it to rev. but if i floor it, then itll die if i let it. now when it warms up, it runs alot better and will rev when i rev it. idle also comes down. it did have a code 44 which was a lean code. i bought an o2 sensor and a maf sensor and installed the o2 sensor. code has went away as it would pop up as soon as it went into closed loop. but my problem is still there. i did reserch on the cold start valve and from what i understand it only helps with cold starts for like 8 seconds. im going to install the maf sensor today, but i tried unplugging it first and it didnt help at all. whatever it is, only affects it on cold and open loop. any help would be most appreciated. i dont have a scanner that will do obd1 so i have to rely on the flash codes and my multimeter skills and i also have an oscilloscope but im not that familiar with it yet. but like i said the cel didnt come back on since i installked the o2 sensor. the car has sat for a couple years but i did put fresh premium fuel into it. ill update after the maf sensor install to see what happens but im not thinking itll help. btw i will respond quickly as i work out of my garage and have my laptop opened with this thread so i can check things pretty quickly when to guys offer testing procedures or a diag path

Tuned Performance

iTrader: (92)

Chris May

Sorry I didn't get back with you asap. Thanks for the reply. It runs alot better when its warmed up. I did a voltage sweep on my tps. My iac is under 60 on the counts which from my research ive done, that's ok. My block learn is 150 and my integrater is 128. So it's defenitely running lean and adding about 20 percent more fuel. No vacuum leaks found. Temp sensors seems to be ok. It's showing correctly to the ecm from what i see on my scanner anyways. I ohmed out my injectors. All good. I have an identifix subscription and have opened a case with them to help me. Spent an hour on the phone with one of their techs and he seems to think all the sensors are working and I may have some clogged injectors. I have an injector tester that activates the injectors one by one and im going to check pressure drop today to see if any of them are clogged. It's a maf system and it showing good responce on the grams per second. But ill reply later with more diagnostic results. Thanks again