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Jun 2, 2002 | 11:33 PM

desperado_18_2000

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From: S. Mississippi

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i've got a 79 F-150 with a 400 under the hood. It has a stumble. I've tried everything i can think of to correct this problem. The only things i haven't tried is the choke on the old motorcraft 2bbl and swapping the carbs completely. too much Emissions stuff for me to fiddle with the carb too much. Thanks in advance for any help!

Jun 3, 2002 | 08:12 AM

shazam

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From: Porterfield

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Have you checked the Accelerator pump on the carb. Sounds to me like it's not getting that little shot of fuel when you step on it .

Jun 3, 2002 | 10:17 AM

desperado_18_2000

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From: S. Mississippi

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I went out and played with it a few minutes ago. If you quickly blip the throttle it stumbles bad. if you slowly bring it through the range it will rev on up. Almost near WOT it backfires and shoots gas out of the carb? whats the deal?? Thanks in Advance!

Jun 3, 2002 | 11:07 AM

Fastcat

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With the engine OFF look down the carb and give it a shot with the throttle. You should see a squirt of gas. If it doesn't the carb need a power valve. The backfire sounds like a lean problem when accelerating.

Jun 4, 2002 | 03:47 PM

brents

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Is the timing set OK?

-Brents

Jun 5, 2002 | 12:09 AM

desperado_18_2000

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From: S. Mississippi

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unknown about the timing. It also has hot start drag after its been ran about 15 minutes... it doesn't want to start for like an hour till its cooled. the starter and starter wire are new, but that doesn't mean anything. also could be the timing because i havent' been into this engine much.

Jun 5, 2002 | 12:12 PM

teschwab

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From: nc

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don't be afraid of the smog stuff. just label the lines and keep a few notes or snap a polaroid picture. i agree that the stumble could be coming from a fuel starvation deal. the timing should be set using the under hood decal. follow it to the letter and you won't have any problem. i would suggest that you only try one thing at a time so you can get a feel for the exact problem.