I have a 2002 Grand Cherokee with 225,000 miles (hooyah!) on an I-6 . After driving for long distances (at least an hour on the road) then idling for extended periods of time, it seems it starts misfiring. RPMs drop to about 500 and will not rev past 1200 without dying completely.
This has happened a few times in the following scenario:
We have 3 kids and often visit family out of state. We’ll drive for several hours before pulling off at a rest area. To minimize the amount of time spent off the road and to save the hassle of unloading/loading all the kids, we’ll leave the car running (to keep heat/cool air in) and either myself or my wife will run in to use the restroom and get snacks. The vehicle may idle for 10 minutes before the issue presents itself. It seems that if we turn the vehicle off and rest for a few (3-5) minutes, the problem will resolve itself and we can be on our way with no more issues.
Check Engine light is on but only throws a code for an EVAP leak.
I don’t know a whole lot about cars. I thought it could be time to replace spark plugs but this issue doesn’t happen often and it seems only in these specific circumstances.
Any advice would be appreciated!