[Cinabug]

I'm having a terrible time with my 93 Jimmy, and I thought that someone here could help me.

Problem - Starts up fine and runs for about 15 to 20 minutes, then the engine just shuts off. If I wait for about an hour, this problem repeats itself. It's not overheating, and no warning lights come on. My mechanic was kind enough to rescue me when I was stuck, and he checked to see if motor was getting fuel and spark. Apparantly it was getting both. We had it towed to his shop, where it has been all week.

Things Mechanic Has Replaced

Fuel pump and filter
Fuel relay
EGR Sensor
Coil
Spark plugs and wires
Distributor Cap
Rotors
Ignition Module
Fuel Injection spider
Computer

He has also put it on his diagnostic computer, and nothing comes up as being wrong. My mechanic is highly rated in my city, and also a trusted friend of mine. He is totally frustrated about my Jimmy, and refuses to quit on it. Any ideas or suggestions from anyone would be greatly appreciated at this point!