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73-87 Chevy _ GMC Trucks => Performance => Topic started by: 81-n-done on January 11, 2011, 06:50:25 pm
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My 81 GMC Sierra SWB has a 350 in it. I know that the truck wast driven very much before i bought it, but I am having an issue (after getting a full tuneup)
When I punch the gas, the engine bogs down to the point of almost dying for about 1 full second, then it takes off like a bat outta heck. Its just nt making sense to me, I feel like if she was staring for gas that she would putter out after I had punched it and gunned it for a bit, sucking the gas out of the carb reservoir. Am I wrong here? What do you think it could be? I think it is better when the truck is really warmed up too, if that helps.
I checked out the vacuum lines already too, and my local guy took a look at the carb and said he doesnt see why it would have issues.
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Did you check the accelerator pump discharge?
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after you check the accelator pump check your dist. pick up coil etc and wiring, adv weights and springs. My thinking is that it may be an ignition problem when timing is advanced. They're two wires that go to the dist shaft that pivot and therefore is a wear point; check those too.
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is this an auto? it wouldnt be a timing problem since hes not reving at 4k, i would double check your carb also what kind is it? factory quad? did it run like this before?
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Is your detent cable hooked up?
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Did you check the accelerator pump discharge?
I will check this out when I get a few minutes and some daylight. Thanks
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Did you check the accelerator pump discharge?
My mechanic buddy has a new carb that we are gonna throw on to see if that solves the issue.
If it was the accelerator pump wouldnt I be having issues when I accelerate every time? not just when i punch it?
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after you check the accelerator pump check your dist. pick up coil etc and wiring, adv weights and springs. My thinking is that it may be an ignition problem when timing is advanced. They're two wires that go to the dist shaft that pivot and therefore is a wear point; check those too.
Just a thought here, And along the same lines as 1980c10. You said the problem started "after a full tuneup". What gap did you set your plugs at when you changed them? Fuel-Air-Spark. Throw a timing light on her, and check your Hold down bolt.
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It could be a lot of things, but I also would check accelerator pump first. Besides there are few things easier to check. Just look into the primaries and see if it squirts when you flip the throttle (engine off).