I just bought a 93Z28 and it seems to be running a little rough. Upon cold starting it idles at about 750rpm and never goes any higher, I just thought that to be strange since you would think it would idle up when it was cold and fairly cold outside, talking 40s?

Also when coming to a stop the car will hold at 1000rpm for about 10sec before coming back down to its original idle of 750rpm. There are no check engine lights and I don't have a code reader right now. Am I basically stuck until I get a code reader? I was thinking the datalogger from TTS.

I didn't know if this sounded like a common condtion that could be ID'd fairly easy or not, just hoping I guess.

 

Since you just bought it, you should do total lookover and maybe a basic tune up. Such as plugs, wires, air filter, fuel filter for a start. Then look over sensors that maybe corroded or not working. Time and patience. Good luck.

 

what mods do you have?
and unplug your MAF and see how it runs. (Its normal for it to run rich)
then check out your TPS sensor. Located on the right side of your TB. (Throttle Body)

 

I forgot to update my signature. It's a 93 Z28 6M. It has a flowmaster exhaust with no cats on it, BBK Throttlebody, KN Intake, 160 thermostat,and the previous owner claimed it had a Hypertech tune on it but didn't have the tuner itself so who knows. Also before anyone gets on me about the flowmaster exhaust with no cats and any of the other mods just know I did none of them. This car also being a 93 uses a speed density computer so no MAF.

 

I got a hold of the original owner the other day, he told me the idle got a little rough after installing the BBK throttlebody. He said since the day he had done that the idle was low and would hang around 1000rpm when driving and comming to a stop. So is that simply the throttle stop not being adjusted right? Doesn't seem like it since it's low at times and high other times.