Engine has been cutting out during normal driving

CJ KRAL

MEMBER
2002 JEEP GRAND CHEROKEE
4.0L
6 CYL
2WD
AUTOMATIC
214,500 MILES

What has been happening is the engine has been cutting out during normal driving. The engine will suddenly stop running with out any warning. The electrics such as lights and radio will still work, but the engine will not start back up. This would happen when accelerating, decelerating, idling, hot or cold completely at random without warning. I check around the engine and it is getting fuel pressure. The only thing that I notice is that a plug was loose. This plug is one of a set three large plugs by the coolant tank. Two of the plugs are resting against the tank, but the one that was loose was on the far right and exposed. I did some trouble shooting by starting the car then wiggling the plug and the engine did stop like before and I tried starting it again and it was giving the same symptoms. I secured it in place, but it happened again. The only solution that has been working when my engine stops is resetting the computer by dislocating the battery for five minutes. I am wondering if I am missing something. Should I check anything else or is it that plug and it just needs to be more secure?

1 Reply

CARADIODOC

MECHANIC
33,916 POSTS

If you can wiggle the plug and the engine stalls, it sounds like you found the cause. The things to look for are corrosion on the terminals, and if one of the female terminals is stretched. A stretched terminal will make intermittent contact. That can be caused by prolonged vibration with the terminals sliding back and forth against each other very slightly, but more commonly by someone poking a test light or voltmeter probe in too far. Some terminals can picked, with a small pick, to squeeze them tighter. Some have to be removed from the connector body, then be squeezed very lightly with a needle nose pliers.