Ok, when I start the car, the idle is a little rough. It starts about 1000 rpms and bounces about 200 rpms, gradually coming down to settle at 600. It also comes down with the oil pressure. Oil pressure starts off at 60, and eventually comes down to almost redline. That is when the idle begins to smooth out at 600 rpms. This whole process takes about 10-15 minutes of driving. The cap, rotor, and wires were all replaced about 150 miles ago, along with a plug I was having problems with. Could this problem be caused by a clogged fuel filter? How about some of the temp sensors on the front of the intake? I was also thinking a leaking ninth injector...or any injector for that matter. I'd appreciate it if someone could give me some ideas. Car is an 85 Z28 w/ 88 IROC 350. All stock at the moment. I want to get it running well before I start some mods.

 

anyone?

 

Stock at the moment? Which ECM are you using?

It is common for the TPIs to start at a high idle, then gradually step down as coolant temperature increaes. The older models would tend to maintain the higher idle RPM longer, and newer models would tend to drop RPM faster as temperature increased (all programming).

 

All stock for now. Using the ECM that came with the motor.