Context: We just replaced the motor in our 2000 4.0 MT with another 4.0 from a 2005 LJ. Finally got it to run after diagnosing and fixing multiple reasons why it was not starting (starter was bad, ignition coils were bad, cam sensor was not lined up correctly with TDC.)
The motor runs now and it runs strong at idle (does not sound like it misfires and no odd vibrations), however, if we let it idle for a long time (like getting it to temperature to burp the coolant) or even a small blip on the throttle causes a misfire-like sound and the motor stalls out. Usually it does not throw a code before or after it stalls, but it did throw P0353 once after stalling.
The spark plugs are brand new, so I would doubt that is the issue. We used the coil pack that came with the used motor we bought, since our old coils were pretty shot. Where should I start and what all should I check with diagnosing and fixing this?
The motor runs now and it runs strong at idle (does not sound like it misfires and no odd vibrations), however, if we let it idle for a long time (like getting it to temperature to burp the coolant) or even a small blip on the throttle causes a misfire-like sound and the motor stalls out. Usually it does not throw a code before or after it stalls, but it did throw P0353 once after stalling.
The spark plugs are brand new, so I would doubt that is the issue. We used the coil pack that came with the used motor we bought, since our old coils were pretty shot. Where should I start and what all should I check with diagnosing and fixing this?
