Ok my friend has a i think an 89 sc. Here is the thing. It ran great and then one day it started doing this. The idle is at 2000 to 3000. It is running good boost. And the computer is not reading anything. So we replaced the mas air sensor, throttle pisition, and the idle air sensor. And it still does this and there one other thing the brakes are acting soft and brake light keeps comming on. also when you clutch the car in gear the rpm drop for a second and then go back up this only happens when you clutch it while in gear out of gear it does not change it if you clutch it. We have tried to look for vacum leakes with ether but have not found anything any ide what it is??
thanks
jr
thanks
jr