Questions and Answers

Jeep Comanche Surging Q. Hi, I have a 1988 Jeep Comanche Pioneer, 2WD, 4.0 liter with a manual transmission. To sit and idle it seems to do fine, and when driving it's okay, until I start to top out a gear or, in a long flat straight away where I'm keeping the throttle in the same spot it want's to surge real hard (buck and jump)! If I let off the gas just a touch it smooth's out!

Also sometimes when it idles way down like at a stop sign it will die. When I restart it sometimes the engine will rev way up for a minute or two, like the gas feed is stuck!! I have replaced fuel filter, TPS, plugs, plug wires, distributor cap, rotor button, cleaned EGR valve.

The truck had been setting awhile when I bought it about three months ago. It hasn't gotten any worse nor better. Seems to do this more when the engine is cold! Should I just push it off a cliff, and go back to driving my 1977 DJ5F Jeep???

Thank's so much for your time,
Jason

A. Knowing this vehicle as I do, there are two distinct possibilities. The first, and most likely, is a bad Throttle Position Sensor (TPS) or a weak Crankshaft Position Sensor (CPS). There was a countermeasure CPS to repair a weak signal.