I have an 02 liberty, with 3.7 and auto. I've rebuilt the motor, had the trans rebuilt and a lot of other replacements/repairs back in early 2018. It ran great for a year or so. This winter, around the time of severe cold, I had to replace the battery. I also ended up putting it on a charger/booster unit to get it started. I only mention this due to the approximation of the time the issues started. I can't say for certainty the battery replacement was the exact time this issue started but its near. What happens: I drive the jeep, no determined amount of time and suddenly it dies. Sometimes it starts right back up, other times it takes a few minutes of sitting before it starts up again. It will crank over fine just not fire. Things I have tried for isolation: -Fuel pressure - Good when it dies, stays consistent at about 50psi even when it has to sit. -I have a viper remote start/alarm system. Pulled the fuses for this in case it was defective. No change -replaced the PCM thinking maybe I fried it with the battery boost/replacement - no difference -had to replace the TPS, had thrown a code but I think it was a victim of when it failed and I pumped the pedal trying to get it to respond. I broke the old one trying to remove it for inspection. -wiggle test on various sensors/wires -replace the oil pressure sender, due to leakage (oil light does not come on prior to fail) -swapped the ASD relay - no change. -No codes are set by this event. I have had some codes in the past but these have been present when it ran ok. They are: P0442 - evap small leak P0445 - evap gross leak (hoses by tank need replaced) P0734 - gear4 incorrect ratio. no idea why this pops up, it runs fine I've had a code 18 and some other bus related error but that was a one off and not at the time of the issue. When it dies, it can be sitting at a light, driving highway speed, driving city speeds, basically no pattern to it. In all cases the engine was warmed up so it should be in closed loop. In desperation I took it to a shop for further diag and they put about 90 miles on it over 2 weeks. It ran perfect for them of course. I got it back, one trip to the store and it starts the dying issue again. Other times I can drive for hours and it never happens. I'm lost on this one, if anyone has ideas on what to try I'd love to hear them. I've debated replacing the cam and crank sensors but if they were faulty I'd expect a code logged to them as well. The other thought I had was to jumper the ASD relay to see if it will run through whatever issue it has and throw up a code.