hello everyone im a newbie here my son has a 1998 chevy 1500 pickup we got for him at a used car lot. the truck always starts and idles well. but around 2000 rpm it breaks up bad. many opinions about fixing it. we changed plugs the wires are good .fuel pump in the tank is very loud.i have 350 in my van and the fuel pump can barely be heard.should i change cap rotor and ignition module or go to the fuel spider setup. all fuses are good and autozone says they cant pull a code from it because ecm has no power.if that is true how is the truck running at all any help would be awesome thanks all