I just got a 1985 z28 tpi and it idles a bit high in park. When you hit the brakes the rpms drop real low and it stalls sometimes. I replaced a couple spark plug wires because one was burnt and it felt like it had a missfire going on. Now it seems to have smoothed out some but still has the stalling issue and high idle in park. Thanks for any help

 

Have you checked for vacuum leaks ?

 

Like the brake booster

 

Brake booster or intake / vacuum hose leak causing high idle. You can check with carb choke cleaner or a unlit propane torch.

 

Vacuum Reservoir had water in it got all that out and the vacuum line running to it and from the t fitting to the check valve was really weak didn't see any holes in it tho but was probably collapsing in on its self. So I replaced that and the PVC hose to the throttle body because it was to short and barely holding. It seems to be running much better now still has a vacuum leak on the lines running to the egr solenoid since they are broke off at it. I'm gonna cap them since the air tubes and egr is deleted.

 

Welp its doing it again, not as bad as it was tho. It also has a strong fuel smell from the exhaust and gets really bad gas millage

 

Welp I put Msd street fire spark plug wires and did a new distributor cap, new rotor, and new ignition coil. I also adjusted the tps and idle air control and now it seems to be running close to normal got the check engine light off.
Sounds like who ever had it before put a more aggressive cam in it because its got a little shake and a bit of a lopey idle to it