I have a 1999 F-350 7.3 diesel with a 6 speed manual transmission. The truck has 116,000 miles. Recently, I drove the truck and it ran fine for about 60 miles and then acted as though it was starving for fuel. If I kicked the turbo in, it would just start to slow down until I would pull-over to the side of the road and let it idle for a minute and then it would run OK as long as I did not kick in the turbo. I changed the fuel filter and it seemed to correct the problem, however after driving the truck for about 20 miles, it did the same thing. I have replaced the fuel pump twice and compared the fuel flow into the fuel bowl with that of a 2001 F250 7.3 that a friend has and mine is quite a bit less. I pulled the bed off and checked the gas tank canister and all looked OK. I put it all back together and the truck ran great for about 20 miles, I had the cruise control on and it just started slowing down and acting like it was not getting enough gas. I pulled over and let it idle and was able to drive home as long as I did not give it too much pedal. The next day it ran fine, however I did not drive it 20 miles nor did I get into the turbo. There seems to be a problem getting fuel to the fuel bowl, but only after it is driven several miles and the problem temporarily goes away after the truck sits. I was going to take it to the dealer as I have run out of ideas, but after reading some of the comments, I thought I would try this forum. Any suggestions would be greatly appreciated. I have bee fighting this problem for about 4 months.

 

Is there something floating around in the fuel tank that finds it's way to the pickup screen clogging it? Did you do the intank mods? Is it possible that someone may have vandalized your truck by putting something in the tank? How about your fuel pressure regulator.

 

Well, you came to the right place, welcome to FTE. Here's a bump for the possible fuel problem experts..

 

Did you take apart the white plastic thing on the fuel pick up inside the tank? There are 2 cylinder shaped screens inside there. My guess is those 2 screens are clogged up. Did you check these screens?

 

Can you here the pump priming when you turn the ignition on. ?

 

Take the fuel pressure regulator apart and check the poppet inside. Sounds like the o-ring on the poppet is faulty. The FPR kit at ford has everything U need except the vibralock sleeve. Order that from guzzle on this site.

 

What is the fuel level when this happens? If It is low the fuel pick up could be sucking in air. Try keeping the tank level above 1/4 tank ( 1/2 would be better ) to see if the problem goes away. If this corrects the problem, you will need to do the in tank mod as suggested above.

 

Thanks for the quick response. I have not done any tank modifications. Is the fuel pressure regulator after the fuel filter housing? We checked the fuel flow into the fuel filter housing. When we pulled the canister out of the tank (to check for fuel or air leaks) we did not notice anything in the fuel and we cleaned the screen on the bottom of the fuel intake line. We did not take the canister apart, but wondered what was inside. I will take the bed back off and pull the canister apart and check the screens. Will I run into any problems taking the canister apart? We have always thought the problem was somewhere between the fuel pump and fuel. This problem has occured when the tank was full or at any level.

 

While you are in the fuel tank go ahead and do the in tank mods. Be sure to install an in line filter between the tank and fuel pump. NAPA has them and should be rated for suction. Good luck on your fix.

 

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Where, specifically, between the tank and the fuel pump is the filter to be installed and do you know what the <?xml:namespace prefix = st1 ns = "urn:schemas-microsoft-comffice:smarttags" /><st1:City w:st="on"><st1lace w:st="on">Napa</st1lace></st1:City> part number is?<o></o>
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The in tank mods are here Welcome to guzzle's In-tank Hutch Mod Web Page

 

The FPR is inside of the housing where the hard line connects to the top of the drivers side of the fuel bowl. -- Careful when removing the hard line as the factory housing is VERY fragile -- There is a spring and brass plunger inside and the regulator seat seals this brass part against the fuel bowl.

The FPR on a stock fuel system is one of the most under-rated and most overlooked items in the fuel system.

If the heart of the fuel system is the pump, then the FPR is its soul.

Any damage or cracking of this seat will not show up during startup, flow test or idle. It will majorly effect your fuel pressure once you get moving.

 

I believe that the in fuel line is on the bottom of my fuel filter housing and the return line is on the top. If I remove the return fuel line from my fuel filter housing will that expose the fuel pressure regulator or is it removed from inside the fuel filter housing?

 

I expierienced the same symptoms you are describing less than a week ago. I cleaned the screens and tank out just as f350-6's great picture shows and that solved my problem. FYI the fuel pressure on the lift pump should be between 30-80 psi, seems like a pretty broad range to me! but that is what I was told.

 

Doing the above in bold will fix your power loss issue.
You need to clean the junk from the screens.