I have an issue with a 88 K1500 5.7l. I've replaced the fuel pump, fuel pump relay, fuel pressure regulator, fuel injectors, fuel filter, egr valve, egr solenoid, did a complete tune up, replaced the map sensor, tps sensor, ignition coil, ignition control module, idle air control valve, and it's still no better then when I started. It also has a crate motor that was installed about 15,000 miles ago. Any other suggestions?

 

did you try a compression test on each cylinder?

 

The problem found with my truck ended up being a bad distributor! Thanks everyone for your ideas!