I have a '93 s-10 Blazer with 4.3 Vortec. The vehicle has been running fine until the other night. Vehicle started, idledand ran fine, about a mile down the road it started loping real bad. Decided to turn around and head back home that is when I noticed that I had to stand on the brake pedal. Complete loss of power assist. When I arrived back home check engine light on, extreme lope from engine, and still no power assist to brake. Any ideas or suggestions?

 

Probably a blown vacuum booster. Disconnect the booster line from the front of the booster and plug it. Start the engine. If you looping idle has been fixed, then the booster is mostlikely blown. The next test would be to run it, then shut it down and pull the booster line (with check valve) off the front of the booster. If you do not hear a woosh of air being pulled into the booster, the bladder inside is blown.