Vehicle: '93 S-10 Blazer, 4.3 CPI
Problem: Recently started out and the vehicle started and ran good. About 1/2 mile down road started running very rough. Decided to stop and turn around and head back home, I had to stand on brakes to get it to stop. Every time I had to stop it dies. Once back home very rough idle. What with the brake issue my thought is brake booster bad. I replaced the booster. Now the only time it will start, and run smoothly, is if I have vaccuum hose disconnected from booster. The instant I plug vaccuum hose to brake booster engine dies. Will only start if I disconnect vaccuum hose from booster.

Any ideas or suggestions appreciated.

 

Will it eventually start if you plug the vacuum line to the booster? It is possible that the IAC valve (on the throttle body) is all the way closed and may have stuck closed due to the faulty booster.