Ok ive been working on get my blazer back running for awhile now. It started out needing a fuel pump. So i installed a new one(aftermarket which everyone has told me are junk now after i installed it). Ever since then Ive had a hard time starting it. I can hear the fuel pump when i turn the key on and off. Usually after it sits for awhile it doesnt want to start. But when it does i drive it and if i give it to much throttle it seems to fall on its face and just rev up to around 3000 rpms and not really go anywhere. But i can ease on the throttle and it will rev all the way up. It will even do this when its not in gear just sitting in park. Please help me im loosing my mind!

 

I bet it's the pump... Sorry dude! Check you're fuel pressure.

 

Is the only way to go is with a gm pump?

 

I would check the fuel pick-up line on the pump to insure you don't have a high pressure leak in the tank. As previously mentioned check fuel pump pressure, and be sure you did not restrict ,crimp, or bend a line when you R&R'd the pump.