I have a 97 GMC Sierra with a 350 vortec V8. Only 106,500 miles too. 3 weeks ago she shut down in the middle of the road. After 2 tries she started right back up and ran fine for a week. We changed the plugs and did an oil change as well. Right after that we were running errands and she wouldn't start up. Finally got it and again she ran fine for another week. Well this morning taking my son to school we had to stop for an ambulance. We started to go after he passed and she shut down, started up again on her own 3 times. Finally quit completely. Pulled over, put her in park, turned off anything on(radio etc..) and she started right back up. While letting my son out the door she accelerated on her own while my foot was on the brake and again after I put her in park when we got home! I have been told fuel pump multiple times but close friends who have worked for Chevy say CRAP. They whine coming out of the factory. Was also told maybe sending unit or EGR valve? Please if you have any ideas, I don't want to get stuck on the raod with my kids, Thanks, Corinna

 

I was going to start with the ignition module. I don't know about the accelerating on its own thing though. It may be a bad Computer, have that checked.

 

Well we bought her in January of 05 and we had the computer Updated. She has since shut down 2 more times. I was idling at a signal and she shuddered really bad and quit. I expect a truck to shake more than a car does. She has a big engine but it felt like she was gonna fall apart. My hubby undid the battery to reset it and she hasn't shut down in almost 2 weeks, though she still shudders and shakes ALOT more than normal. I am afraid to take it to a dealership. They always list 10 other things to fix. We have been being told she needs a new fuel pump cuz it whines, yet she starts right up with no problems. Hope this update helps, Thanks

 

I'm very familiar to those symptoms. Ive had 3 cars that had fuel pump failure. my ramcharger shook like hell at idle and shut down a couple of times b4 it went dead, I think its the fuel pump because it whining but before you go and pay I suggest buying a pressure gauge and check the fuel pressure or when it shuts down and refuses to start, unplug the fuel filter and try to start it. if it doesnt shoot gas everywhere then its bad and must be replaced. good luck hope I helped...
p.s the self accelerate thing could have been the computer self adjusting fuel pressure to keep the car running. on newer models, the computer is responsible for keepin the car running so when it senses the motor stalling it increases fuel so.... in other words that may be the reason that happened.

 

I woudl first start off by checking fuel pressure. Since it's intermittent problem it's kind of a shot in the dark but fuel pumps are really bad for going out. But when they go out they normally slowly die off instead of one day working and the next day they don't.

 

Have you checked the fuel pressure yet? Is your truck throttle body injection? Should be, just wanting to make sure. If so next time it dies look into the throttle body and see if fuel is being dumped in. If not, have you ignition module checked. If it tests good then your pick-up is bad. The computer program shuts the fuel off when no spark is detected.