Michael,
Check for restrictions in the exhaust system. there might be something loose
in the cat. conv. or muffler that rolls back and plugs the exhaust flow
when the truck is on an incline. That would certainly explain the loss of
power.
Joe
Michael Graziano wrote:
>
> All,
>
> Worked on the aforementioned truck today. Got to experience the problems
> first hand.
>
> It's an '86 GMC Sierra 3500 Dually Pickup with a lifting dump bed and a V8
> (I think it's a 350 with a 2 barrel carb). It runs fine on straight and
> level road. Plenty of power. Within 100 feet of driving on an incline
> (even 10 degrees), the engine seems to die. No power, although it
> continues to run. I get a brief surge of power, then nothing, brief surge,
> then nothing. It smoothes down once we get the speed down to 25 or 30 mph.
>
> Things I've checked.
>
> Fuel Filter at the carb - changed a dirty looking filter.
> Fuel screen in the tank.
> Exhaust - new dual exhaust with NO catalytic converter
>
> I tried to check the timing, but the timing marker on the timing cover is
> gone. There seems to be plenty of power when power braking it (giving it
> gas when your foot is on the brake), so I would think that timing isn't an
> issue.
>
> There's a hard to get to mechanical fuel pump, so I was unable to check fuel
> flow from it. How often do the mechanical pumps go bad?
>
> Also, I tried going up the hills in all gears (it's an automatic, so 1, 2
> and D) and it gives trouble in all of them. Even first. On the straight
> and level, the owner said he's had it up to 70 mph on the highway with a
> load and no problems.
>
> Is it me, or does this seem like a fuel issue? Or can it be transmission
> related? Does it sound more like a fuel delivery issue, or a carburation
> issue?
>
> Sorry to bomb the lists with this again, but I need to use this truck this
> coming week.
>
> Thanks to all who offered their ideas on Wednesday. Anyone have anything
> else I should check? And no, the answer's not "Get a Ford." <grin>
>
> Mike
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