I've been trying every bit of information I can find to stabilize the idle on my '86 305 Iroc tpi. When it first starts (cold) it idles almost what seems right but give it a rev and it idles much higher. Then when I shut it off and then restart it anytime its warm, the idle goes up to about 1700-1800 rpms. I have replaced the Iac motor, cleaned the passages, set tps voltage (.54) checked for vacuum leaks, checked for codes,(getting a code 32 EGR). Testing indicates EGR and solenoid to be OK. I am at a complete loss for a solution. Anybody have a similar problem/fix for this?????
Help.

 

That's somewhat normal, especially considering that the factory tach tends to read high. If you connect a diagnostic tach, you may find that the actual RPM is lower.

Cold start target idle for an '86 TPI is usually around 1,400-1,500 RPM, then decreases as the coolant temperature increases and an internal ECM timer elapses. Even on a warm restart, the target idle RPM starts high, then drops rapidly as the CTS information is received by the ECM and the timer counts out. My '86 TPI used to do the same thing, even with the factory replacement upgraded PROM. After a custom PROM burn or three, the "problem" no longer exists.