Last weekend while I was driving all of my gauges started bouncing left and right, then it stopped and they settled down like the truck wasn’t running. I stopped at a gas station and made sure the battery terminals were tight and when I started the truck back up everything was working fine.

Today I went out to the truck and when I tried to start it I got nothing except the tach and speedo needle moved up maybe a quarter inch and stayed there. I rechecked the battery terminals, looked at the grounds under the hood and under the truck and they look ok, and I checked every fuse and didn’t find any blown. When I tried to start the truck again it started up and then died after a few seconds. Now every third or fourth time I turn the key it’ll start up and run for a few seconds and then stall. Any help would be greatly appreciated.

 

Hey! did you ever find the solution? Because im having the same problem. thank you

 

This is reminiscent of a fuel pump relay with contact issues or an ECM not telling the fuel pump relay to engage or a fuel pump / Ignition circuit fuse issue .

 

When it comes to electrical issues, there are so many possibilities. But one of the MAIN causes I've seen of electrical problems in vehicles is the GROUND.In all vehicles, there are 3 MAIN grounds. The frame/Chassis, the engine block, and the body. Why 3? Many reasons, but motors sit on motor mounts. These are usually some form of rubber/neoprene or other non conductive material. If you look at the negative battery cable on your silverado, you will see 2 wires coming off the battery. (Unless you added some additional). These 2 wires go through an inductive ring that is the current sensor. It monitors the amount of current being used and talks to the alternator to tell it how much charging to do. Anyway.... these two wires.... the thicker of the two goes to the engine block; front passenger side. Sort of right behind the tension pulley for the serpentine belt. There's also another wire on this bolt. I would take that bolt off and clean the metal and the ground wire from the battery nice and clean. The second wire from the battery, which is thinner, goes to the frame/chassis of the vehicle. If you follow it, it will be in the front passenger side of the vehicle near the radiator, but ON THE FRAME. Remember I also mentioned the BODY of the vehicle has to also be grounded. If you look at the firewall area of the vehicle, driver side, you'll see 2 ground cables bolted to the firewall. One goes to the hood and the 2nd (Looks like a braided strap) goes to the engine block in the back. This connection is notorious for going bad over time. It fray. ALL of your electronics in the vehicle gets it's main ground from this point. It is a PITA (Pain in the @$$) to get to that bolt on the block. What most people do is get some more braided strap, leave the old one connected, add the new one to the firewall bolt and attach it further up front. Right next to the alternator is a great spot. The alternator mount plate has an extra threaded hole in it.

Anyway; I would make sure that ALL of these 3 grounds are in good shape before proceeding. Without good grounds, you can't count on anything else being accurate when troubleshooting. I can't tell you how many people have paid for (Because the mechanic; even the dealership) told them they needed a new battery, or a new alternator, or a bunch of other things. In the end, the problem was a ground or the current sensor on the negative cable. For what it's worth, I believe on the 2008 the current sensor comes as part of a new negative battery cable. It does on my 2007 silverado.

I'm not saying this is your problem or going to fix anything. But I am saying that the negatives/grounds on the chevy's (especially this generation) had issues. A lot of people who get into adding aftermarket stereo systems and such automatically do what is called "The Big 3" wiring upgrade. That's these 3 ground points I explained. They put in beefier wires to handle more amps for their sound system. Little do they know, they are actually improving their entire electrical system. Remember, the manufacturer will go as cheap as possible. Wiring contributes to weight. The more weight they can reduce, the better they can improve fuel economy and other issues. This isn't the old days where we had the battery just to start the car, turn on the lights, and turn on a radio. Today's vehicles are ALL ELECTRONICS. Modules, sensors, computers, etc. Most people who do "The Big 3/4" wire upgrades, usually just leave all the original 3 grounds in place and just add 3 more thicker wires and bond them together. Anyway; make sure the frame/chassis, body, and engine block grounds are good, sturdy, not fragile, etc. Then you can trouble shoot from there.
Mike