I got the speed sensor replaced today and that fixed that problem. Thanks Lou for your input.

I would have thought that the V-10 would have great pulling power. My new travel trailer is 5717 lbs dry. When pulling it up the smallest incline I have to down shift and my speed drops to about 40 mph. There must be something wrong.

The truck has just over 100,000 miles on it. Five speed tranny and of course the V-10. We replaced the exhaust from the muffler out and a new fuel filter. Tried a new mass airflow sensor today and that really did not make much difference. The truck just does not have the power that my Excursion with a V-10 had. Any suggestions what could be causing the lack of power?

 

What gears do you have in the Super Duty compared to the X?

 

Have you changed the spark plugs lately? Have you checked the fuel pressure?

 

What year SD V10?

If at 100k in mileage...looks like you might be due for a spark plug change.

Any chance your TT is dragging the brakes?


biz

 

When you check the fuel pressure, the gauge should say 30 lbs. Also may be the o2 censors. They work just like your mass air flow but on the exhaust end. They will cut power as well.

 

Not enough information is given to even begin to guess as to the cause.

It could be anything from air delivery, fuel delivery, exhaust restrictions, transmission trouble, aerodynamics, driving style or mechanical issues.

 

Sorry, I forgot the year. Its a 1999. I am not sure of what gears it has. I can go about 40 mph in 5th gear. I purchased the truck about 3 months ago so I am not sure on the history of how it was maintained. If the body and paint are any reflection of how either one of the two previous owners treated it. Then it must have been very well maintained. But I could be wrong.

I have not tried any of your suggestion yet. But I will do so. I can turn a wrench but most often it is the wrong way. Other wise, I know enough to get me in trouble and not out.

I don't think that the brakes are hanging up on the TT since it lacked power pulling either one of the TT.

Here is a list of what I have done since I bought the truck.
New brakes
New clutch
New exhaust: muffler and pipe out.
New ball joints
Gas filter
Oil changes
New air filter

Driving style when not pulling on the highway is 65 to 80 mph. I don't do any hot rodding anymore. I have mellowed with age. With the trailer I stay around the 60 to 65 mph when I can.

You all have given me good things to look at. Thank you.

 

I believe it's because you have 373 gears. A lot of other members have complained about the v10 with 373s

Take a look at this tag on your door and find where it says axle and post the code underneath it. Here's a pic for example:

As you can see it says axle and the code is right underneath. Mine is 4N which means I have 4.10s with limited slip

 

After you take the truck out on the highway, check the cat. If its cherry red, it is clogged.

 

Horse puckey! A V-10 should easily pull 5700 pounds, even with 3.73 gears.

 

It may pull it but you'd be surprised on how many people complain about how the V10 is a turd and low and behold its cause the 373s.

 

The axle code is 31.

 

I have a 5.4L with 3.73 gears. I regularly tow well over 8000 pounds without issue. I stand by my original statement.

 

I bet it is really 3L. That would mean you have a 3.73 Limited Slip rear differential. The other possibility is 37, which is a 3.73 open differential.

 

Some have other opinions on how their vehicle should pull. Could it be him and the 373 gears? Possibly, or it could be a combination of that and another issue of the truck or just a clogged cat. I'm just throwing suggestions out there.