My Camaro has been doing this for a couple months now. Before I thought nothing of it, but lately It's been really starting to bug me.

Some of you guys know of my cold start problem. Car runs like complete crap unless you warm it up at least 5 minutes before driving. While warming it up, you have to give it varying amounts of throttle. If you just hold the throttle in one spot (giving light throttle that is), it will run funky. Sounds like It's hesitating, and misfire can be felt here and there. In extreme cases, every once in a blue moon this can also result in intake backfire. Car WILL NOT hold idle if started cold. keep searching between 400 - 1000, stumbles and will sometimes stall. If driven before warm, extreme hesitation and misfire (and again sometimes intake backfire) occurs under moderate throttle. If you punch the gas (Not WOT, but maybe 50 - 60%), it picks right up. A code 44 is also the usual result of driving when cold. When the car does throw a 44, it runs like poo. It idles like you had just started it cold, and misfires badly. Once you start driving and get some speed going, it runs better but the only way to get the SES light to turn off and the engine idle OK again is to restart the engine.

Once warm, it usually doesn't give me any complaints. But now I have this new issue that has been around for a couple of months.

Once warm, it holds idle perfectly fine at about 700RPM. But, if you were to shut the car off and restart the engine, it idles like *** again. Not quite as bad as from a cold start but drops to maybe 500 - 600RPM, some misfiring can be felt and a slight amount of hesitation can be felt on first takeoff or two. It doesn't matter whether you shut the car off and go into 7-11 or turn it off, count to 5 and restart. It will do this every time. It's almost like there is a sensor going rogue somewhere and the ECM has to relearn itself every time you start the car (Not anything like if you reset the ECM but you catch my drift).




Things I've done and can rule out:

- Replaced o2 sensor, about 3 weeks ago.
- Made sure TPS and idle air were properly calibrated. The TPS passed all test with flying colors. Voltage, resistance and open circuit test. The minimum air position I adjusted the best I could, But I COULD NOT get the car to hold a steady 450 - 500RPM idle with the EST bypass connector unplugged. It idled horrible, rapidly bouncing between 300 - 600 RPM.
- Serviced IAC, although I am just going to say F it and replace the stupid thing. Only $30 at advance better safe than sorry. Although I don't see how an IAC could be causing a problem of this magnitude.
- Replaced CTS several months ago.
- Replaced cap and rotor with MSD.
- Replaced fuel filter.
- Replaced ignition module. Made no difference and the Jegs module I found in the dist tested OK so I put it back in.
- "Rented" an Electronic Spark Controller from advance, and made no difference.


Anyone got any ideas here?

 

What type of injection system do you have? Cause it might be an injector or two.

 

305 TPI

 

I do not have TPI but you might want to look into what is called a "cold start injector". Most 80 to early 90s fuel injected models had them. If you have it, it shouls be mounted on or close to the throtle body. They are mainly used when the motor is cold and during acceleration.

 

The cold start to the best of my knowledge is only used during cranking when, well, cold. It is located on the drivers side runner.

 

Fixed the problem guys.

The MAF was bad.