I have a K1500 Z71 with 5.7L and while pulling a 17ft boat when pullung up a hill it will start running rough and service engine light comes on. After service engine light comes on and back off on throttle, then engine will smooth out. Keep driving and after so many cycles of ignition switch light will go out. It has had all O2 sensors, converters, muffler, plugs, wires, cap, rotor, module, replaced and the GM dealer still does not know what is wrong, when the service engine light comes on and diagnostic tool is hooked up it always shows Rapid Engine Missfire. The only time this happens is around 2000rpm and pulling a grade where the transmission shifts from O.D. To Drive, and if you keep going it will stop on its own and will not do it until the code is cleared or let it go until the light goes out on its own.
have the same problem?
Saturday, September 19th, 2009 AT 7:47 PM