I bought a 1982 GMC 1/2 ton 4x4. It was running fine until a couple days ago. I got in it and pulled out it sounds like a pack of firecrackers under the hood.I have changed the plugs, wires, dist cap. and it still does it. sitting still idling or revving up it does not miss. The only time it does it is when I pull out and step on the throttle. at about 1/2 throttle is when it pops. 4 speed small block. any information on what this might be would be appreciated. Thanks, Greg
I have a 1985 GMC 3\4 ton with a 350 4 speed, and it did the exact same thing. All you should have to do is either pick you up a bottle of fuel additive at the gas station that boosts up your octane or buy a more expensive gas. But if that doesn't help, try adjusting your timing. I hope this will help. Tony
