[Jeep Jerry]

Hi Guys,
I recently had my T.P.S. , fuel filter, and fuel pump replaced on my 97' Cherokee I-6 4.0 L engine about 2 weeks ago. I had this done because of an intermittent rough idle, and engine backfire. I originally tried to correct this problem by using Proguard fuel injection cleaner, and running BP (Amoco) 93 octane rated ultimate. My assumption was that I had obtained some bad fuel, but when the 93 octane and Proguard did not improve my problem, my Jeep was taken to a local independent mechanic. At first , my mechanic could not get the problems of an erractic idle, and engine backfire to repeat. However, after a few days in his shop, the problems finally surfaced. He ran diagnostics on the Jeep, and concluded that the Cherokee must have a faulty T.P.S., fuel pump, and filter. He replaced all of these items for me at the tune of $1200. Much to my chagrin, two weeks later (today), I am now having the same problems again (ie. erractic idle, engine backfire, jerking hesitation with acceleration ). However, this time, I have a check engine light on the dash that want go away. To make matters worse, this problem is intermittent once again. I am totally exasperated by this problem. I am very hesitant about taking my Jeep into my local mechanic again. I really don't want to get torched for another $1200 bucks. Does anyone have a clue as to what is going on with my Cherokee? This vehicle has given me good service, and I only have 86K on it. I really would like to keep it running, but at the same time, I don't want to sink more cash in it as part of a guessing game.

Jeep Jerry

[balloo93]

Swing by a AutoZone and have them pull code on it. The OBDII should store any codes tripped.

Have you ever replaced the O2?

[Jeep Jerry]

Thanks Balloo93 for the tip. I have never had the O2 sensor replaced. My spark plug wires and spark plugs were replaced at 60K. My local mechanic ruled out faulty spark plug wires as well.