Hi, I have a 85 z28 5.0 FI. I just got it about two weeks ago and I need some help. I have tried just about everything I can think of and I'm still having the same problem. When cold, the car will start but I have to stay on the gas and I can hear it spitting out through the intake. It runs fine when it is warm except that when I let off the gas, the car will not decelerate. It will stay at whatever speed I let off at which is not too big of a deal (it's like cruise control). Then when I put it in park, it will rev to about 2000 rpm's. If I shut it off and then back on, it will run fine at about 850 then slowly start to climb back to 2000, then drop down and go back up again.

The SES light will come on at lower speeds. When I went to get the codes the only one I got was three quick flashes then back to code 12 (but I'm not sure what those three quick flashes mean). I do know that I have changed the IAC, cleaned the TB and checked for vacuum leaks (of which there are none). I have 5.0 volts at the TPS, I pulled the MAF and the car shuts off so I assume it's good. I also changed the coolant temp sensor. I've run out of ideas and I really just want the car to run. I'm not sure if not having a fan relay would have anything to do with any of this (the guy who had it before me just hard wired it) but I'm waiting on the relay to come in. Thanks for any help