I have a 87 S10 Blazer, it seems to back fire and stall the same place every day , it will back fire and then stall , you will stop and wait a minute and it will start the run fine. However sometimes it will do this 2 to 3 times in a row, but eventually start and run fine. I have also noticed that at constant speed, it will rev up and down. Please Help

 

you pullin any codes?

 

Welcome Mitch.

Codes would help.
It could be any number of things. Plugged cat, timing, tune up, one of the sensors. Really need more info about the engine and what you have done so far, if anything.