Car Tech forum: 2000 Jeep Grand Cherokee - Dies ONLY when hot outside

Maybe you should try seeing if the fuel pump is overheating. Does it still break down if your tank is more than half full?

It could also be a broken temperature sensor somewhere, but this is very unlikely. Its probably something that has to do with the fuel injection system.

my 99 jeep does the same,cant be be the fuel pump,might be a sensor.the tran over heat light comes on.no clue any ideas?????

There are numerous issues with this vehicle, I still own one. If its only happening when warm and there are no codes for the check engine light OR a number of erroneous codes this would tell you there are multiple problems. The first thing to check is the battery connection from the main wire harness. Most 1999-2004 jeeps wire harness is elevated an heavy, the vibrations will cause a hair line crack and will cause various error codes depending on what was drawing power at the time. Once this is checked, check your MAP sensor, then you EGR. A couple of other possibilities are crank or cam sensor.