Truck wont go over 40 mph
 

I'm new here and new to Diesel ownership. I just got this 2000 f550 7.3 to help with my lawn business and a couple days ago started shaking at about 40 mph and it would go away. Now the truck doesn't go over 40 mph and the engine starts to loose power and slow down no matter how much gas I give it. Someone suggested the fuel pump in the rail and I changed that but it does the same thing. Any suggestions? Has anyone seen this before? I thank you in advance.

Do you have a way to scan for codes?

make a fuel pressure guage..screen in the tank can be clogged, take the fuel line off the inlet of the pump and blow air back into the tank and see if that helps..Fuel filter? has the filter been changed?

Yep I had a similar issue with my O2 7.3 and the injector plug under the valve cover was disconnected only one side of the motor was operating properly could not get over 40. Fixed it for $.50

how old is the oil in the truck. my truck all of sudden started acting up blowing white smoke and would not pick speed up every one i talked to was saying turbo or injectors i checked both and no problems talked to a old diesle guy and he told me to put new oil in the truck so what the hey it was worth a shot so changed the oil this morning and now the truck runs perfect the oil was bad. not saying this is your problem but it is worth a shot.

Make sure your fuel pick up in the tank is not cracked when you pull it out to clean the screens out. We had ours doing something similar the other day and noticed that if you were on a hill with the amount of fuel in the tank it ran fine. Turned out that last time the screens were cleaned the plastic had been cracked on the pickup and would allow the truck to suck air when the crack was not submerged.
That one took a minute to figure out too. The crack was not very noticeable

Boost tube blown off?

I had similar problem. Let it warm up idle for a good 20 minutes and see if that helps. If helps Your turbo is not getting warmed up enough before driving it.

99 f250 slows down after 50 mph
 

Hey guys, I'm new to this forum. I've had this truck for about 4 yrs now. I was having these exact same issues mentioned above. The computer scan gave me codes to change the ICP sensor 1st, then the EBPSensor & lastly a local diesel mechanic told me to switch the fuel pump because it wasn't starting any more. I have since changed all those out & Im back to the original issue of the truck slowing down on the expressway as I hit 45-50 mph. Any insight would be helpful. Im thinking of trying a couple already mentioned things such as oil change & fuel filter change, but anything else?

Thanks,