98 Gmc 2500 Hard Single Jerk While Driving

FixaFro420 · February 13, 2009

1998 GMC 2500 4x4 while driving it makes a hard single jerk mostly on hwy. no engine or trans codes. It first started doing it when shifted into overdrive. Tranny shop says its not the trans. I have tried New injectors,plugs,wires,cap+rotor,coil,module,fuel filter, pump+sending unit, and pump relay. It doesn't do it all the time. I'm thinking maybee computer or ignition. Truck does have 180k miles and 500m on fresh rebuilt engine. I have changed the trans fluid, front/rear diffs fluids, transfer case fluids and fluids looked ok no shavings.

ChevyTech007 · February 14, 2009

1998 GMC 2500 4x4 while driving it makes a hard single jerk mostly on hwy. no engine or trans codes. It first started doing it when shifted into overdrive. Tranny shop says its not the trans. I have tried New injectors,plugs,wires,cap+rotor,coil,module,fuel filter, pump+sending unit, and pump relay. It doesn't do it all the time. I'm thinking maybee computer or ignition. Truck does have 180k miles and 500m on fresh rebuilt engine. I have changed the trans fluid, front/rear diffs fluids, transfer case fluids and fluids looked ok no shavings.

If you used an aftermarket cap replace it with a GM part. One other thing to look at is the 3 wire connector at the coil. The wires are bad about breaking inside the insulation at the connector. Get a new connector with the wires and wire it in a few inches above the connector.