Titled this low power with a question mark because this is the first 7.3 I have owned and I am not sure if this thing has a problem reducing the power or if its normal.
The reason I am thinking something is wrong is because this thing feels like a slug. It is a regular cab dually with a flat bed. The only time it will really pull is if I am close to, or WOT. Normally driving I have school buses riding my bumper while trying to accelerate without holding her wide open.

Some things to consider:
Recently on startup in any temperature, and if I wait for the WTS light to go out or not, the truck will sometimes start roughly on the last crank with a puff of white smoke. The smoke is a single puff.

I also just replaced my leaking windshield. It was leaking on the computer and I lost the operation of these known components: horn relay, shift interlock solenoid, and the wiper motor.

Some things I have done recently: fuel filter, air filter, fuel pump, in tank pickup mods and filter cleaning, tightened all intercooler hoses.

 

 

Ok gotcha, thanks. L99, mileage is around 136k, automatic. I don't have any gauges.

 

An EGT gauge would help narrow it down to a fuel or air issue (if there is an issue). Air issues result in high EGT's while fuel issues result in lower than normal EGT's. My truck came to me live tuned and I can't detune it so I don't know what a stock set up is like but I have heard that they are sluggish. When you're kicking it in the sides trying to get it to go faster does it blow a lot of black smoke out the exhaust?

 

The OEM configuration is underwhelming compared to other trucks. That's one of the reasons that the engine has been well-known for its reliability.

I'm not sure what you're comparing it to but yes, it's a slug in stock form. It's a medium duty engine that is built to be a work horse and not a hotrod.

If you don't have any other indications of an issue then I would consider that your truck is working fine.

If you want more out of it there's plenty of threads (and vendors) out there that will help you get more out of the powerplant.

 

These aren't fast trucks, even tuned up. They feel fast tuned up and make a lot of power but keep in mind, they are, at minimum, a 7,000 LB vehicle and very old technology. It won't take off like a gasser v8. It makes a lot of torque, yes, but seat of the pants power doesn't really open up until 2k+ RPMs.

 

A stocker does require quite a bit of pedal to start making good power compared to a gasser, but it's hard to convey what is normal or not without feeling it. My Excursion feels somewhat weak 'till I get pretty far into it, yet I can pull my 13k boat with it reasonably well. I've driven a few other 7.3s and they're all kinda like that, it's a very different response curve and feel than the throttle on a gasser.

Have you pulled any loads? These don't really try to rev up quickly like a gasser will. You might have a truck that feels weak empty but will pull like a freight train. And the perfect analogy just hit me, think of it as a locomotive or semi-tractor. They're not quick no matter how lightly loaded, they're made to pull loads. Your truck probably has pretty low gearing which one would think should make it quicker, but often it has the reverse effect with a diesel.

Look for any smoke while driving and report back. Also, if you state your location a local member might meet you for a test drive to get a second opinion on whether the power is normal or not.

 

I never expected it to be a race car because obviously its not, and I don't want that. I just want to make sure its running right so if I go to sell it, something isn't wrong with it. I haven't noticed any smoke when accelerating. Like you all said, there probably isn't a problem. I just felt like there might be something more.

 

takes a lot to move these old girls ....you could get some gauges to monitor everything ...

 

Something I forgot to add to my post; while they do take more throttle than a gasser to get going good, if you floor it from a standstill it should slowly build power and really start to go around 2,000 RPM. If you don't feel the power rise somewhat sharply as the RPM come up there may be a problem.

 

They are dogs stock, but you should be able to pull from a school bus.