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73-87 Chevy _ GMC Trucks => Engine/Drivetrain => Topic started by: 1986GMCSierra on December 21, 2014, 11:01:37 am
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My stock 1986 GMC 305 has a high idle problem and after she gets warmed up she backfires uncontrollably... i was thinkin the timing might br off a little but that doesnt fix the high idle.. Need help guys. thanks
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Choke being stuck could cause the high idle and also deliver to much fuel and
fouled the plugs causing your backfire
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wheres it backfiring out of? but high idle could be a vacuum leak, the vacuum lean would cause a lean condition and the lean condition might lead to higher temps and cause pre detonation? again this is 100% a guess but might be plausible
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wheres it backfiring out of? but high idle could be a vacuum leak, the vacuum lean would cause a lean condition and the lean condition might lead to higher temps and cause pre detonation? again this is 100% a guess but might be plausible
its coming out of my exhaust if thats what you mean?
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Check your timing and that the distributor is clamped down tight. Temperature changes in the winter can loosen a marginally tightened distributor, which will then rotate with the rotor shaft to a more retarded setting. Retard it enough, and you will get backfires (actually, afterfires, since they are coming out the exhaust, not the carb).
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Check your timing and that the distributor is clamped down tight. Temperature changes in the winter can loosen a marginally tightened distributor, which will then rotate with the rotor shaft to a more retarded setting. Retard it enough, and you will get backfires (actually, afterfires, since they are coming out the exhaust, not the carb).
ok i will check my distributor thanks