I have a 88 K-5 Blazer when cold it runs a little ruff, but after it warms up it won't restart unless you hold the gas pedal to the floor, after it starts and clears out, it will idol but if you ease in the the throttle it stalls if you mash it to the floor it will run but spits clouds of black smoke. When it is doing this it also seems to be trying to suck a lot of air through the throtle body its really loud even with the air cleaner on. I put a new throttle body on it today and still having the same problems. Please help.

I have a 88 K-5 Blazer when cold it runs a little ruff, but after it warms up it won't restart unless you hold the gas pedal to the floor, after it starts and clears out, it will idol but if you ease in the the throttle it stalls if you mash it to the floor it will run but spits clouds of black smoke. When it is doing this it also seems to be trying to suck a lot of air through the throtle body its really loud even with the air cleaner on. I put a new throttle body on it today and still having the same problems. Please help.

Any codes or check engine lights?

Check engine light is on but i cant get it any where to have the codes pulled and not sure how to do it myself with out a scanner.

Check engine light is on but i cant get it any where to have the codes pulled and not sure how to do it myself with out a scanner.

http://www.troublecodes.net/GM/

Post back codes.

Ok the only code i can get it to put out is a 12 and I dont see that one on the list

Ok the only code i can get it to put out is a 12 and I dont see that one on the list

Code 12 is a computer system pass code or OK.

How is the fuel pressure?
Any leak fast down?
Is egr valve stuck open?
Have you checked exhaust back pressure?