loss power

[gabe2000]

I am driving. My truck for 2 weeks after 2yr. Of restoring. It world fine at first now it loss power at 35 miles per hour. It auto thm350 n 250 inline. I have been reading n suspect the Even vvalve. ??????
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[gabe2000]

I suspect the EGR valve but it plugged so not sure now.....any ideas

[Clyde65]

so after 35 mph it shuts down or has no power? what about up to that speed?

[64shortbox]

Do you mean it shuts off completely at 35 MPH or - if you let off the gas a bit so the truck only goes 35MPH or less it runs OK? If the truck runs OK at 35 MPH or less I would suspect a fuel delivery problem. A plugged fuel sock because of rust & scale from sitting 2 years? A plugged fuel filter? A pin hole in a fuel line or fuel hose? A weak fuel pump? Or here's one that drove me crazy on a 350 Chevy - the eccentric on the camshaft that runs the fuel pump was worn and barely worked the fuel pump arm causing the fuel pump not to deliver enough fuel to the carb to run more than about 45 MPH or so.
Here's a run down on cars I've had in teh past with fuel delivery problems & thier causes:

1956 Buick Special: Crack in rubber fuel hose @ gas tank.

1959 Pontiac Star Chief: Pin hole leak in metal fuel line against frame.

1972 Buick Stage 1 GS Riveria: Animal hair covering the fuel pick up sock.

1974 Chevy Van: bad fuel pump eccentric.

1962 Pontiac Catalina: Tri-Power, 4SPD car: The middle air filter was plugged.

Unfortunately there are lots of things to check on, even a new fuel pump could be bad. Hope this helps some.

[gabe2000]

i am going to replace the gas pump. Also i installed an under bed gas tank.....I read that i should run it without the gas cap...but I don't how that effect a carb. engine.

[gabe2000]

When it gets to 35mph , its losses power and stalls but doesn't turn off. it just rolls without power. I let pedal off and it return power. so i return home and have not move since which I need the truck for working at the house.

[joedoh]

plugged fuel filter.

[luvbowties]

Originally Posted by gabe2000

i am going to replace the gas pump. Also i installed an under bed gas tank.....I read that i should run it without the gas cap...but I don't how that effect a carb. engine.

It needs a vented cap--can you SAFELY try it with gas cap off?
Sam

[64shortbox]

What joedoh said. I see you have the see through one in the fuel line but there is still the factory one that is in the carb itself. I would check that first.

[gofastnut]

3rd vote on fuel problem. Is there a small piece of rubber line on the suction side of the pump? How does it look? If it's not perfect, change it. Also check in the carb for another filter, if installed backwards, you'll get similarly poor performance--if it runs at all.

[gabe2000]

The Carb. Is new from the salvage yard and I replaced it's filter but I'll check again. I am going to replace fuel pump because it cheap. And try driving without fuel cap. I am going to post my under bed tank soon. I'll update next week. Thx
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[TehNewGuy]

Sounds a lot like my problem I had in my 66 when I first got it, it didn’t have brakes at first so I didn’t know for a few weeks. When I did the brakes and started driving it around at 20-25 it got boggy, would not run right. From there it got worse as I drove it, after starting the truck it wouldn’t idle right then eventually didn’t idle at all. I decided I would rip out the entire fuel system and replace/ rebuild everything. What I found, just like gofastnut said, the rubber at the end of the fuel line IN the gas tank was disintegrated and the entire metal line was full of small bits. More I ran it the more it sucked in until the fuel pump was no longer pulling fuel like it should. After cleaning the gas tank out and repainting it I went over to my fuel sending unit that sits in the tank, blew it out with some air and noticed it had some surface rust just below the elbow that sits outside underneath the cab. When I went to hit it with a soft wire brush it turned out to be 5 pinholes. since I didn’t have a another one I cleaned it and ran hose from the fuel pump to the sending unit line and shoved the end of the hose past the pinholes to get it home. On the way back it ran Alot better.

Things I did so it might help,
Cleaned the carburetor filter
replaced the inline fuel filter and fuel pump
replaced all fuel lines from the sending unit to the carb, did not reuse any old hose or metal lines
cleaned out the sending unit line and replaced the metal line just after the sending unit on the outside of the tank to under the cab
Empty and clean the gas tank

sorry this is so long and hope you get it running soon!