Ok, I'm sure this has been asked before but I wanted to bring up an issue I have been experiencing. I have no check engine light on my dash. My jeep has left me stranded twice. I have tried starting it after driving it and it starts up runs about 3 seconds and dies. Do it over and over with the same result. Took it to my mechanic twice. Once he said my head unit (stereo) had burnt wires. Repaired it and it started up. Second time he tells me he disconnected the amp and started back up. So, I'm assuming that this is an anomaly and maybe he disconnected the battery twice and that's what caused it to start back up. Several times the jeep shakes a bit like it wants to shut off and the coolant gauge goes to the red with the check gauges light then drops to n ormal temp and jeep runs fine. What can that be? Why could this be happening? Mechanic tells me its not the key. I mentioned the crank position sensor and he ruled it out since there is not check engine light.