I have a 1989 full size blazer with a 350 TBI. It will idle fine but when you give it gas it falls on its face and will stall once in a while. I replaced the fuel pump assembly, fuel filter, all sensors and rebuilt the throttle body and still the same problem. It doenst show any codes. Any ideas??

 

ive seen issues like this when the EGR valve goes bad. my buddy had the problem where when he tried to drive normal with it or holding like 35mph it would die or run like crap. the egr was opening wide open at low rpms causing a huge vacuum leak

 

If you have a 350 you should probably get a EGR block off plate anyways

 

I bet your timing is off (retarded). You need to set it to 0* with the EST bypass unplugged (black plug, brown wire by wiper motor along firewall). You can usually rent a timing light at advance or wherever if you don't have one.