2000 S-10 Blazer
cranks and has good spark and gas but wont fire.
I have changed the plugs,cap, rotor and wires and have a bright blue spark jumping out to ground. I have fuel up to the throttle body. I have cleaned the crank sensor and now im lost thinking fuel regulator or computer??

 

Get a fuel pressure gauge and work through 96+ Fuel System Diagnosis. You don't know if you have enough starting pressure until you do this.

 

you can try a trick. turn the ignition key to on and listen for the hum from the fuel pump . you might have to remove the gas cap. if not, turn ignition to off; then try it again. if you here the hum, try to start. if starts you may have a fuel pump going weak. but the fuel pressure test is a real good way to see if your pump is putting out 50 - 60 psi . hook up the fuel pressure guage to the fuel rail fitting and you will see what you have.