chevy 2005 diesel silverado

Truck just stopped going down highway 65mph!! then restarts 15 minutes later. Runs fine for a couple days, then will not start, have towed to shop and starts up again fine for 3 days, they can't find out what is wrong? anyone else had this problem?:frown:

Mine (not a diesel though) does that. I think the ignition relay under the hood is going bad. I tap it and its good for another few days. I havent had the time to get a new relay yet....