Starts great but has rough idle, sometimes dies, boggs down with acceleraton, shifting problems and some backfire. I have replaced just about everything on this truck after the brain melted. Recently after replacing a fuel injector, spark plugs and fuel filter, it was runnng good. o2 sensors and EGR are new also. Computer indcated shift solenoid - I replaced them both yesterday and it's still runnng terrible. Hope someone can help me

 

Check the throttle position sensor (TPS) and fuel pressure.