Same old bucking problem

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Jan 12, 2004 | 08:16 PM

skeneguy

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Joined: Nov 2003

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From: Vancouver

Same old bucking problem

O.K., I’ve heard a couple of these bucking stories and wondered if anyone can shed light on my particular problem.
1982 F150 I6. Came out of long storage with the expected drivability problems. Got a fairly extensive tune-up. New carb, EGR valve, intake manifold gasket, PCV valve, plugs, leads, rotor and cap. Drove much better, but still had a slight bucking problem with gentle use of accelerator, however it sailed through emissions testing.
After a couple of tanks of gas, I thought I’d try the snake oil route and put in a bottle of ‘Fuel Up’ fuel system cleaner. The more I drove on this tank of gas, the smoother it got, not a hint of bucking. Another tank of gas with no additive and within 5 miles the bucking returns! My question is, what does the additive do to improve the drivability? and what can I do to improve it without putting in an expensive additive each tank? Is it a timing issue related to grade of gas, or a mixture problem at the carb.
Any thoughts would be appreciated.

Jan 12, 2004 | 08:47 PM

35l911

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From: oxon hill, MD U.S.A

the tank and carb has varnish in it thats clogging the nozzeles in the carb i had the same problem sould have used syable (gas stableizer) when storing the truck with gas in the tank your going to need to clean out the fuel system if not already done and overhaule the carb

Jan 12, 2004 | 08:48 PM

rainbowATF

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From: Elyria, Ohio

Bucking

Water in gas from condesation while sitting. Fuel cleaner probably helped; but is a carb solvent; but something like STP Gas Treatment has methyl alcohol to absorb water and burn it. One bottle per tank; repeat if necessay next tank. Otherwise drop tank and clean it out.

Jan 12, 2004 | 09:13 PM

skeneguy

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From: Vancouver

Thanks. I don't need to overhaul the carb, it's new. Tank might be another issue. I know it was stored with a full tank, but no stabilizer, although I've been through about 4 full tanks now, so thought any condensation would be long gone.

Jan 12, 2004 | 09:52 PM

Samsonitesamsonite

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From: Bellingham, WA

i had a similar problem, andjust curious what your timing set at? i had to fine tune mine and the bucking went right away after i did that try setting it to around 16 BTDC

Jan 12, 2004 | 09:59 PM

skeneguy

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From: Vancouver

Haven't checked the timing yet, but this is where I'm starting to suspect. What was your timing set at when it was bucking, was it within spec?

Jan 17, 2004 | 06:58 PM

skeneguy

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From: Vancouver

Ok, After messing around, I'm still looking for suggestions. Some days seem worse than others. Took it out today on the highway and it felt a bit lumpy. After 15 mins, switched off and it dieseled a bit, first time it's done that. Got home and checked the timing, 6* BTDC as it say's on the under-hood sticker. I moved it to 10* BTDC and it ran awful, tried it at 8*, no better, so I moved back to 6*. Didn't go lower as it didn't idle too good. As I said in my original post, new carb, new EGR, new plugs, new leads, new cap and rotor. Any other suggestions please?

Last edited by skeneguy; Jan 17, 2004 at 07:00 PM.