i have replaced the ecm, tps, the distributor and still nothing. I am gonna recheck all the grounds today. Any input would be great. by the way 90 gmc jimmy 5.7l 4x4. I am thinking about converting it to carb.

 

while i am not sure how a 1990 mdl/yr nor a 5.7 at that would be wired or setup some general knowledge says check your grounds 8 times and then a 9th to be sure. Verify you have pulse from the wires at the PCM and verify that whatever system actually runs your injectors is providing its signal pulse cleanly and that it is reaching the PCM. also, dont fire the parts canon.