Codes pointed you to the ECU, which does look like it was replaced with a junkyard part, jy's usually write on them like that.
As far as the cam sensor yes i have heard up here from those incl. Dave that they can cause you to konk out. However when mine went bad it ran ok, not great, but would have real trouble starting when hot.
Testing them is imho is hit and miss, this is one where i keep a spare from the junkyard to swap in they are cheap like $5. in fact i am running one now because the autozone ones (2) turned out to be the original problem, this was confirmed. At least the jy has mopar lol.
Do you have a scan tool and what does the live data show you if anything

 

Hey guys, my 97 ZJ started to die once in several days but then it began to die more and more often but it started again everytime until one day that it never started again, the culprit was the ECU, i took it apart and re-solded every pin inside it and no problem since that, my 2 cents i hope this helps cheers!!

 

ok here is the latest. i ran a live scan using a way too expensive scanner from a mechanic and nothing unusual came up. i received the CPS today so i changed it out. what a bear getting to it but its done. turned out the one in there was aftermarket evident by the weak magnet. so that might have been the problem (i sure hope so) or the original owner had this same issue and changed out parts attempting to fix it but it was never resolved so he sold it. he clearly replaced the computer and the CPS at some point.

 

same problem popped up a couple times since my last post on this subject. it seems to die while driving, but sometimes catches and keeps going. could the fuel pump be intermittent? how about the cam sensor, would that cause it? i am not sure what else it could be.

 

Fuel pump is almost a must change item at that age. Pressure tester is a must also..$15 at harbor freight.
There are not one but a few tests for the fuel pump, it can tell you alot. If the regulator is bad the bleed down test will show it. If either of the two little fuel filters are plugged, well, ...and with that much age and mileage what do you think. One of the filters is on the pump inlet and the other is actually called the regulator/filter, in the round thing up top of the gas tank.

Just observing the pressure while running you might also catch it dropping out or low.

If you already did the crank sensor with a new MOPAR and not another knock off brand of any type you should be ok there if the wiring harness is good. Cam sensor, well, they call it the distributor switchplate, I went through 2 new ones from the AZ before I went to the junkyard and got a used OEM which is still performing like a champ. I'd still have the old one if I hadnt broke it fiddling with it. Same thing, weak magnets. But imo these will cause starting more than running issues. My case, the AZ ones actually threw codes as well.

 

When my PCM went out I got no codes. No nothing. My symptoms were like yours. I changed the Cam sensor. It didn't fix anything. I was told by local mechanics that if the CAM or CRANK sensors went out, I'd get a code. If your getting fuel it is possible its the PCM. .

 

this weekend the jeep stalled and would not restart. cool. now i have something to troubleshoot. began with the spark plugs. no spark and traced it back to the coil. replaced coil and it started right up. i only have a few miles on it but really, really, hope this is it. i have not heard of a coil being intermittent so this might be a separate issue. hopefully not.

so the bad news. drove the family 3 hours to take part of the Panemint valley days and when this happened we were on our way to join an all day run to some pretty cool places. i spent the day making repairs. the next day (today) was better, was able to go on an easy run to a cool location.

 

on the way home the jeep cut out but i was able to restart it. back to step one...

 

Sounds to me like my previous fuel pump experiences.
Currently my 95ZJ 4.0L started a few hic ups. Then a stall in stop and go traffic. Did restart. Then a loss of power running steady on rough road last night, power bog for about 200 ft, then no problems and kept going. My biggest suspect is fuel pump.
Had pump failure on the XJ previous, power die, then refire and go.
Have also had pump failure time when I had to thump the gas tank near the pump mounting and the pump refired.
So my experiences with intermittent power loss is fuel pump failing. The problem progresses to complete failure.
It's a messy job, but someone's gotta do it. Keep your tank level at half max or less. Easier to pull than when full.
You can exchange only the pump, and keep the original sending unit, cheaper this way.

 

thanks peep. i was thinking the next time it happens i would not attempt a restart, but to pop the hood and depress the fuel rail valve to see if there was any pressure in the line.

 

as far as the fuel pump goes does it matter if its a mopar part or is aftermarket OK?

 

so doing some reading and the PCM looks at the following information during operation:
battery voltage
engine coolant temperature
crankshaft position sensor
intake manifold air temperature sensor
MAP sensor
TPS
Crankshaft position sensor
Park natural switch

in some of these cases if the PCM does not receive the signal its looking for it will cut the fuel and/or adjust the timing via grounding of the coil. it seems that I might want to focus on those areas. I recall some of the gauges dropping to zero when this happens, but when the engine starts cutting out I usually focus on the RPM gauge to see what is going on. that could be an indicator where the signal is dropping off. I am thinking I might want to go to a junk yard and pick up some of those components and swap them out as part of the trial and error without having to spend money on new parts.

 

more clues...

yesterday while at a light the jeep slowly started to idle rougher and rougher until it stalled. i was fixated on the rpm guage and then all of a sudden it died, and just as the left turn light turned green with 8 cars behind me. with no time to check the fuel pressure i placed it in park and cranked it over a couple of times before it restarted. the first couple of cranks it seemed like it wanted to start but would not then finally started and off i went.

no check engine light but when i got home i put the code reader on it and P0351 came up. previously after the check light came on i would get the 0351 code (ignition coil, missfire. etc) and a 0420 code (cat converter, O2 sensor). so i think the 0351 happens first then as a result the 420 code is triggered. i tried to pull the freeze data from the reader but it said it was not supported. i assume the PCM does not support it? if i can get that data then perhaps i could recreate the situation and find the problem. BTW, in a google search on those two codes a few owners have had the same exact problem but no solution was ever posted. one guy switched to super unleaded and claimed that solved his problem.

 

For a guy with such a tricked out jeep this should not be taking you over 4 months to solve, or did you buy it and not build it. You have codes for ignition coil or circuit, and likely a failed clogged cat converter. I would start there, did you ever check the fuel pressure since July?

 

have not checked fuel pressure since july. but, it stalled again today at a spot i could check the fuel pressure and it did have pressure ruling out the fuel pump. so its electronic. i need to go by the junk yard and pick up spare electronic parts and start swapping them out one by one.

ya, this one is kicking my ****.