My F150 4.6L has a two program chip that I have had on for four years. The engine died when I was driving on 4 occasions in the last few months (electrical death all gauges to zero and the battery red light on) but started up right away when I removed the key and restarted. The check engine light came on. The engine was running rough prior to the last episode but not the previous ones. Figuring I was going to need to have the computer hooked up at the dealer, I removed the chip, disconnected the battery etc and ran the car for a couple of days - still running rough but no electrical problems although the check engine light has come on after a day or so. If it hadn't been a total electrical wipe out on the instruments it would seem like dirty fuel although it has come from the same station forever. But my question, if they reflash my computer at the dealer can I still use my chip or does it have to be reprogrammed? Secondly how long after the battery disconnect do I have to drive for the computer to have info that may help them diagnose the problem.

Sorry for the long question but I think there is more unbiased info here than the dealer.