1973 k20 350 intermittent bogging under load

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adamsalikin

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lake country, BC
First Name
adam
Truck Year
1973
Truck Model
k20
Engine Size
350
1973 Chevy k20 350
New fuel pump
New fuel filter
New air filter

Truck will randomly bog down under load past about half throttle. If I pump the accelerator a few times it goes back to normal for about 30 seconds then Boggs again. Happened a couple days ago then went away on its own, then showed back up again today. runs perfect in neutral and revs up to limiter no problem.

Tried cleaning out carb, timing seems normal, no cracks or anything on the fuel lines that could be starving it of fuel.

Anyone got any ideas?
 

PrairieDrifter

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Mason
Truck Year
84,79,77,76,70,48
Truck Model
Suburban k10, bonanza k10, k30, k20, c10, gmc 1/2ton
Engine Size
350, 350, 350, 350, 350, 350
Sounds like a bad pump to me. Fuel delivery problem anyways.
 

adamsalikin

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1973
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k20
Engine Size
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Check fuel pressure and volume. Quite a few bad pumps out there.
That’s what i was thinking, but the pump was replaced about 2 weeks ago. You think it’s possible the pump went bad that fast?
 

fast 99

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81,85
Truck Model
K20
Engine Size
350
That’s what i was thinking, but the pump was replaced about 2 weeks ago. You think it’s possible the pump went bad that fast?
I bought 2 pumps in a row that went bad in less than 60 miles. If pump ends up being bad buy Delco, Delphi or AC.
 

PrairieDrifter

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Mason
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84,79,77,76,70,48
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Suburban k10, bonanza k10, k30, k20, c10, gmc 1/2ton
Engine Size
350, 350, 350, 350, 350, 350
That’s what i was thinking, but the pump was replaced about 2 weeks ago. You think it’s possible the pump went bad that fast?
Fuel pumps are junk these days. I did 5 or 6 in 5 years. Eventually ruined the cam lobe, to the point a brand new one would clatter on first run lol. I do daily my truck though.
 

c10dang

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sacramento
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Bryan
Truck Year
1984
Truck Model
c10
Engine Size
350
1973 Chevy k20 350
New fuel pump
New fuel filter
New air filter

Truck will randomly bog down under load past about half throttle. If I pump the accelerator a few times it goes back to normal for about 30 seconds then Boggs again. Happened a couple days ago then went away on its own, then showed back up again today. runs perfect in neutral and revs up to limiter no problem.

Tried cleaning out carb, timing seems normal, no cracks or anything on the fuel lines that could be starving it of fuel.

Anyone got any ideas?
did you ever figure out the issue? Just replaced my fuel pump, fuel filter, vented gas caps, new intake man, new carb, cap and rotor but mine is bogging down under load just like the way you described it.
 

Ricko1966

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kansas
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Truck Year
1975
Truck Model
c20
Engine Size
350
This is the second ^^^one you've jumped into the middle of today. Start a thread for your truck,year,engine,transmission,mods,what's been changed. California emissions or not. The 2 trucks you jumped in the middle of today are not even similiar as to engine,carbureation and ignition. All trucks are not the same.
 
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