mornng cherokee pros

[LeHul1]

I have a 98 xj sport 4.0. for the last three months when i first start my jeep it runs rough while idleing, then it seems to clear up if i let it run about five minutes. if i start it and drive away imediatley it chokes out and back fires and loses all power. if i opush in the cluthch and rev the heck out of it then stomp it while in gear upto like 4 grand, it clears up and runs fine. day by day this problem has gotten worse and worse. one mechanic told me, sounds like a sticky exhaust valve, and recomend i suck a quart of transmission fluid through the pcv hose...run it at 2000 rpm for fifteen seconds then shut it down for thirty minutes...i did that and lots of carbon came out of my exhaust. it did not fix the problem. next i notice the cats were rattling, so i removed the converter and had an exhaust shop weld a straight pipe in and put in a new down flow o2 sensor. still did not fix, only made it worse. now the check engine light comes on reporting a catalyst problem...i did replace the computor with a remanufactured pre flashed one about 6 months ago when i was tracing down a bad crank shaft sensor problem...the jeep is idling rougher than ever now, a mechainc yesturday hooked it to a obd computor which reported all cylinders working correctly. he sprayed brake clean around all the injectors and what not...when he sprayed around injwector 2 it made a bit of a difference but it was not consistent enough for him to think that was the problem. i imagine now i have to put a plug fouler on the 02 sensor to make the check engine light go off, but that does not fix me, i know it dont. what in the world could be making my jeep act this way???? please help!

 

[desertrunner]

I have the same problem with my 97 Cherokee.. my buddy had it in his 91 Cherokee. He actually told me today he replace his throttle position sensor and it went straight away... Because the engine is cold I'm assuming the automatic choke isn't working right with the bad tps until it warms up and the choke shuts off.. he said it was about 30 bucks at autozone

 

[LeHul1]

it was bad o2 senser bank one..also catylst was from contaminated oil..codes cleared, drove 110 miles running perfect now..several hundrd dollars later of course,,,dang jeepz, cant live with em, cant live without em..thanks ya'll