What could be wrong...? I have a 2005 Chevy Silverado...?

I have ut 1600.00 in auto repairs with in the last 3 months. My truck starts to turn off as im driving. It shakes really bad when it is coming to a stop and all the electrical inside also turns off. I have taken it to 3 different mechanic and i have replaced the fuel pump, alternator, air mass flow, converters, and the battery but never fails every time i leave the mechanic the truck turns off half way home. Please real answers because I need to know what is going on. they run a computer diagnostic on it every time and all the repairs ive named above is what iv been told it wrong with it but clearly its not. please help!!!