0 question.1999z 25,000 miles. When i brake the idle comes down. I can go 30 mph and it stays at that speed till i brake and slow down.Car had alot of hp work done to it a few years back but the guy who did it died!!!! I got divorced and never found the paper work for all he did. Car runs like a top but Im sick of it doing that. When i slow down i have to keep my foot on the gas to keep it idling when i stop..Any ideas?

thanks rick

 

Sounds like a vacuum leak,take some carb cleaner and spray around the intake manifold,EGR,TB ect.

If your idle picks up or steadies out you found your leak.

 

I also forgot your IAC or throttle blades may be gunked up.