I bought a 1991 s-10 blazer with a 4.3 off of craigslist strictly to tough truck. The competition is coming up and things were going according to plan until I took the Blazer for a test run last night. I took it for a few passes up and down the road, accelerating hard at times. As I pulled back into my driveway the blazer died.

There is alot of black exhaust smoke and the injectors are dumping alot of fuel into the throttle body. The only way to get it to start is by holding the pedal to the floor, then staying on it to keep it at higher RPMs. It ran fine earlier this week, what would be causing such an increase in fuel supply?

Thanks for any suggestions