I have a 92 Jeep Cherokee which is running really rough. The truck has a plow and has plenty of power (I live in Buffalo, NY and plow 25 driveways with it). Does the job and never stalls! It just runs with alot of hesitation, especially at slow speeds or city driving. I have replaced the plugs, wires, cap , rotor, fuel filter, air cleaner & throttle positioning sensor (the TPS made no difference, I just took a guess). I'm stumped! Can anyone help me out?

Thanks in advance!!!

Mike

 

Does it sit in the off season?

And I'd try pulling the air intake off the throttle body, and use some spray carb cleaner to clean the Ideal Air Sensor.. Also check for cracks in the vacuum line to the MAP sensor.

 

I would say vaccum lines like nick_n_ii said. Good Luck!!

 

X 2 in a vacuum leak. You've replaced just about everything else, in yout tune up, that could cause this. Have you run a bottle of Fuel Injector Cleaner through it, lately? Look around the intake manifold area at all vacuum lines. Bet you have a cracked one somewhere.

 

If the jeep has a lot of miles on it i would do a compression test .. My 93 country has the same problem and i have been replacing parts for a while trying to track it down, with no luck.. She stumbles at idle and hesitates when taking off.. once the jeep gets above about 5mph it runs fine..the jeep also idles really low at times.. So i decided to do a compression test with bad results.. #1 cyl was at 50lbs.. all the others were around 100-120.. do a compression test and see what your results are.. I think cylinders should be around 150-190 and the readings be within 15% of each other.. My jeep also sat with a blown head gasket for 6 years and WAS driven with coolant in the oil by the previous owner.. the 93 only has 150k on it.. and its a shame that it has low compression at such a young age and millage..