Hey guys, longtime lurker, but new poster.
I have a 96 ZJ with a 4.0 engine.
Won't go into massive detail here, but over the past 4 years I have (like everyone else) sunk a lot of time and money into this *&%%$*$^%(%$(%
thing. Love the vehicle, but Chrysler can kiss my ***.
Am now on PCM #3.
Went through all the rubbish replacing sensors, etc. due to random stalling, hard starting, etc.
Finally bought a reman PCM (dunno if it was just flashed or if it was actually rebuilt) from a company called (I think) All Computer Resources or something like that in Florida.
Thing ran like a champ for about a year. Then the symptoms began again.
PCM had a lifetime warranty, so I got a replacement last September.
Ran a little better, but still acting fritzy on occasion.
Then got worse and worse and worse.
Found out it was running really rich, and it had destroyed my Cat.
Did not think the PCM had gone bad, so I replaced my Cat.
Still random dying, so I took it to a different mechanic than the one I had for years. They did a resistance measurement on the PCM. I did not ask what exactly on....I was told if the resistance was less than 5 ohms, the PCM was bad. And they said it WAS bad.
So I bought a reman PCM from AutoZone after reading through many threads here. Ran like a champ!
Then I began to notice going up slight inclines, it would lose power.
Then it got to the point that I could not even go over 50 mph on flat level highway.
So I went back to the new mechanic, only to find that by replacing the cat before I replaced my PCM, the PCM was causing the engine to run rich (still) and it ruined the cat. And....it had clogged my muffler.
SO.....replaced the exhaust system (Cat + muffler + downstream 02 sensor), and now is running great.
Ran an OBD II scan on it yesterday for the hell of it. Came up with a P0351 code....the damnable ignition coil circuit.
Not asking for info on that code....I have been reading up on it, and even though I am getting the code, the engine is running great with no problems.
The only reason I popped in here to post, was just to say you guys have provided all of us Jeep owners with a massive amount of info, and I just want to say thanks.
My ZJ is my only vehicle at present, and being unemployed, I have no idea when I will be able to buy another vehicle, but as much as I hate to say it, first chance I get, I am going to sell the ZJ.
Really irritates me that Chrysler made such a poorly designed vehicle and foisted it off on so many unsuspecting people.
Sure, the entire vehicle is not poorly designed, but the PCM surely was, and even though my vehicle is running great at present, I can never rest easy, as I know just a sure as I am typing this that eventually the PCM or one of the sensors will go out again with in the next year or so......
These vehicles are supposed to be the most rugged and durable vehicles.....
But the mid-90s Cherokee series cannot be counted on due to the crummy design of the electronic ignition and engine system that runs off the PCM.
Hell, I learned to drive when I was 13-14.......on a 1942 Willy's MB and a 1943 Ford....both army jeeps!
Those were rugged, easy to fix, reliable, etc.
I went on to drive deuce and a halfs in the army out of Ft. Lewis, WA in the late 70s, and those also were dependable.....
Just bothers me that the Jeep name does not really mean nearly as much as it used to in terms of reliability.
Hell, if Jeeps were built in Japan, you could depend on them....
But oh well.
Anyway, as long as I have this ZJ, I am sure I will be coming here to find answers to my questions.
Thanks guys for all your help.