I have an 89 5.0 GT, that I recentley purchased from a friend, 145k miles. I recentely had a tune up, oil change, spark plugs, fuel filter, new battery, mass air flow sensor, vacuum hose, IAC valve. The car fires right up and sounds great, but will stall out after idling for about 5 minutes. I drove it yesterday and it stalled out after just a mile and would not turn over again. I let it sit for a few hours and it started right up and I was able to drive it home. It had plenty of fuel, Any thoughts on what to look at next