92 cherokee bucking while passing

[Stve Mac]

Just bought this used last week and while trying to pass a car this weekend at 65, 70 mph the engine was bucking almost like over drive was slipping or something. tried it again with the petal to the floor and after a hesatation she oook off like a raped ape.............any ideas? thanks This happen consistantly at passing at 70mph

[fredjacksonsan]

Tune up maybe? Plugs, cap and rotor. Maybe a set of wires since they might be 14 years old.

[ShakerZ]

just wondering if you ever found a fix for your problem with your cherokee buckeling? ive tried everything to fix it and i cant findt he problem

[AlohaBra]

Originally Posted by Stve Mac

Just bought this used last week and while trying to pass a car this weekend at 65, 70 mph the engine was bucking almost like over drive was slipping or something. tried it again with the petal to the floor and after a hesatation she oook off like a raped ape.............any ideas? thanks This happen consistantly at passing at 70mph

Spark plugs. Use Champions (proven for 4.0L performance...other brands are iffy in this engine...this will not apply to other cars).

[erupert]

I assume that the '92 uses a Throttle-Position sensor. Since it's Not OBD-II, you don't have the luxury of getting the code. I just picked up a '97 at auction and it ran like crap, jerking and stumbling at various throttle positions. The check engine was on and when I pulled the code it was a faulty TPS. Replaced it and it runs perfect.

Since it's under full throttle load, maybe check the fuel filter also? It also sounds like maybe it doesn't want to kick down. Not sure if that's electronically controlled or vaccum controlled in that year.