00 Cav Engine Turns Over, Shuts off after 10 seconds

My Cav just stopped running the other day in the middle of a 15 minute drive. I pulled over to the side of the road, the engine would turn over, it'd start for 10 seconds or less, then shut off. I walked to a gas station, put in some more gas just in case my gas meter was broken (it had been in the past), still same deal, turns over, starts, turns off. We had it towed. Mechanics called us the next day, said it was runnign fine, he drove it around and everything. He said there was no problem. Today, I drove it for 45 minutes, then, on the highway, engine cut off again, and it wuoldn't start again. What could it be?!

most likely the fuel pump is on it's way out. when it dies try banging on the bottom of the tank.

Yeah, you were right. It was a combination of the fuel injector not working and a broken gas meter. I was running out of gas really quickly, but never knew it b/c the gas meter told me it was full.