Hey every one I have a 99 f550 2x4 6 speed with a 7.3 powerstroke. This thing has NO power what so ever. It been gradually loosing power over time but now it cant even do 30 mph any more. I can use 1st and get into second but my foot will be on the floor and it still struggles. It never smokes at all, and it isn't throwing codes. I had one fuel line that was bad and sucking in air so I fixed that and bled the system, still nothing. The throttle response is stupid slow. sitting in neutral I can floor it and it will take at least 3-4 seconds to get to 2000 rpms and sometimes it might hit 3k. Also is is leaking something on the driver side towards the back of the block and it smokes pretty bad but only if I rev it a lot. It even caught fire at one point but I blew it out. If im just at idle it won't leak/smoke. I can't see anything leaking though. I don't have alot of money to throw parts at it so I need help here. Oh its not using the steel tank I have a big aluminum tank on the back. **Note I also don't know all the acronyms I just spell everything out so I know what it is.

 

Heres a boot to the top of the list. To me it sounds like your TPS (throttle position sensor) is bad or going bad. Also do you have any boost leaks on your up pipes? those are the ones that connect to the back of the turbo. If you have a leak you will have black soot all over the firewall.

 

Wow. I guess let's start with what is leaking and what exactly caught fire? Can you tell us what brand and weight of oil is in the motor and what the current oil level is? How long have you had the truck? How long did this gradual loss of power take place before you ended up with this? And again, what exactly caught fire? Motor shouldn't catch on fire for no reason.

 

@F350-6- I think its brake fluid. There is this component that has a line going from the master cyl to this component and it has brake fluid leaking from the side of it. I don't know what it is. It has one brake line going to it then it has a regular rubber hose that goes to the back of the truck. The oil level is within specs buts its time to change it anyway so I am going to change it.
@Pitcrw6-No I don't have any leaks on the turbo that was the first place I looked. I am pretty sure its the brake fluid that keeps dripping and smoking on the exhaust manifold. I am going to fix that to. I didn't even think of the tps assembly. I will be getting a new one and putting it on. Makes sense since it doesn't really smoke or blow codes.

 

Plugged fuel filter. Plugged fuel line. Those are the first things that come to mind.

 

This confuses me. There should be no rubber brake lines going anywhere on your truck until you get to the axles. You have rubber lines going from the frame to the front calipers, from the axle housing to the rear calipers, and a rubber line going from the frame to the rear axle. This shouldn't be related to what your problem is though. I wonder if it's some sort of aftermarket emergency brake system?

 

How's the clutch pedal? Area your describing sounds like the master/slave unit...also, try rigging up a f/p manual gauge off the fuelbowl..#4orb x 1/8npt(f). Get a greasegun hose and a 1/8npt coulper to adapt to liquid filled gauge

 

Yep. Forgot all about that!

 

No its not the clutch at all. I tested the throttle assembly unit and that is my problem. Its signal output is not within specs, not even remotely close to what it should be. Ordered one and it should be here in a couple days.

 

It sounds like you found the problem! Hopefully the new TPS fixes it.

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