I have an 87 GMC Sierra Classic 1500 4x4 it has a TBI 350 it loads up with fuel but only when its warmed up. When it gets warmed up it backfires so loud that it sounds like a shotgun going off next to your ear. I've replaced the coil, distributor cap, rotor, plugs and wires, also the O2 sensor has been check fuel pump relay replaced and the knock sensor is fine to i dont really know what the problem is any help would be great thank you. It also has two tanks and does it on both tanks. I also replaced the Hypertech chip with the stock one and its done no good either. I ran codes on it but it didnt show anything was wrong with it. It runs fine as long as it doesnt get warmed up.
I have a 87 GMC TBI 350 it's loading up with fuel.
- Thread starter JoshG
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