I just bought a 02 Ford explorer. v6 4.0 engine with 66,000mi. It didnt do this when I test drove the car, but as soon as I left, the car stared to beep about five times, then stop, then start again and does this in about a series of three. Im thinking its one of a few things. My gas gauge seems to be a little off and the idiot at the dealership for got to put the gas cap back on it so there was no gas cap for a day? Or, there is an alarm system but I do not have access to it. No lights come on, just an annoying beep. Any ideas?