I have a 2000 7.3l. When I first bought the truck I upgraded to 4" exhaust, and put on the hypertech programmer. I also have all the gauges. The boost was always good. Going down the highway at 75 mph it would hold a constant 5psi or more. It would boost up nice.

Now it won't hardly boost up. I really have to get on it HARD to get it to boost. Then after it does boost up, if I let off of it at all the boost drops back to 0. Going down the highway it hardly ever boosts up. My fuel mileage has dropped significately. I have cleaned out the EBP tube. And now I am at a loss of what to do to get my truck Back

Please any ideas.

 

Welcome to FTE!! Sounds like you have a boost leak somewhere. Check all the boots. Follow the turbo outlet through the intercooler and back to the intake. There are 6 boots you need to make sure are tight. If they are all good, then you might have an exhaust (drive pressure) leak before the turbo. Those are much harder to fix. You have to pull the turbo and put in new "donuts" in the up-pipes, normally. Check for black soot marks between the exhaust manifolds an the turbo collector. If you see soot, there's a leak, and there's not enough drive pressure getting to the turbo.

 

Thanks for the help. I will have to look at that.

 

Cool. Let us know what you find, if you don't mind. We like to hear when folks get their issues fixed and what the actual fix was...

 

Here's a pic of a leaking up-pipe. Link

Edit: Forgot my manners. Welcome to

 

While you're at it, make sure your air filter is good and have a look at the turbo wheel for signs of impeller dusting/wear.

 

Welcome to FTE Mudd. I have had that problem for almost 2 years now. Mine stays real close to 1-2 psi on the highway with the cruise on. If I stomp on it I get about 20psi and 10 psi with the cruise going up a nice hill on the highway. Never been able to figure it out. Tested for leaks, NONE and I am still getting 16-17mpg on the highway so I gave up.

 

All the air boots seem to be okay. I went through and retightened them all just to back sure. As far as the exhaust, I still need to get a better look at it, but from what I can see which isn't much looks ok.