Rough running Jeep Wrangler (1998 TJ) standard engine – no modifications
As a result of having an issue with my Jeep and the fact that I could not easily get the issue sorted without financial pain and the realization that others will/have experienced same or similar issues I hope that by writing this I can help point you in the right direction so you will not have the financial loss I had.
The issue:
I first experienced a problem as I drove a back country sealed road to work one morning, this issue showed it self as a serious hesitation the engine was hunting coughing and a part loss of power like running on three cylinders. Similar to an engine running out of fuel this occurred for a couple of hundred yards whilst travelling at approx 60 miles per hour and after stabbing the throttle numerous times to try and clear the hesitation the engine returned to normal and I continued on my way. I had no further issues that day (travelled another 58 miles nervously)
As I was due to travel from England to the South of France and back (2500 miles) I took the vehicle into Chrysler and they could not get the vehicle to repeat the issue. I drove off poorer for the experience and no further forward.
This happened whether the engine was: hot -wet -dry-cold….Whether half or full of petrol.I thought water may have been in the tank as it felt more of a fuel issue than electrical.
This was completely random there was no pattern. As I suspected a fuel issue I purchased REDEX (petrol fuel injection cleaner sold here in the UK) and although the fuelling improved (I think most vehicles of this age require a injector clean anyway) it did not solve the actual issue.
This now started to happen weekly and then over a month almost (still random) sometimes daily and I was starting to wonder if I was going to make it home or to work … but as always it cleared itself and off I went. Eventually it occurred all the time … I could not clear the hesitation and I limped to a garage on what felt like three cylinders.
The garage changed the plugs/leads/distributor cap & rotor. £160.00 later and still no better. The garage gave up after saying TJ Wranglers have an issue with the distributor (internet chat room research) and I would need to take it to a main dealer (Chrysler)
So I now had it in the Main dealers… they were briefed (on work carried out by the previous garage) they test drove the vehicle and could not get the vehicle to run properly, the computer showed no fault. They then changed the Cam sensor £160.00 (and suggested that the whole distributor might need to be changed at a cost of £275.00) before they did this they decided to change the coil/s and whola…. The issue was solved. To date (two weeks) the vehicle is running like a charm (touch wood)
So if your TJ feels like it is staving of fuel (and you have plenty of it) and missing a couple of cylinders but it clears after a rev or two it WILL get worse to a point of failure. Change the coil or swap out a mates matching coil to see if it this helps. As it happens the coil was the cheapest of the items replaced. If only they had done that first? Anyway I hope this helps someone.

Bump