1989 GMC 2500 5.7L - engine surges and stalls at idle. Loses power at cruising speed. I've already changed, plugs, cap, rotor, wires, fuel pump,filter & lines, TPS, IAC, EGR, MAPP Sensor, intake gaskets, checked vacuum lines, replaced distributor, catalytic convertors, Throttle body gasket and cleaned injectors. HELP - We are at a loss!
Cars & Trucks - Isuzu - Impulse - 1991 Isuzu Impulse
Answers & Comments
Wow you have replaced a lot of stuff. Lets go back to the Fuel pump. When you replaced it did you replace the hose between the pump and the sending unit. These are common for splitting. Have you hooked up a fuel pressure gauge to check what pressure you have? It should be real close to 13 psi and should raise to at least 18 or 19 when you pinch off the return line.