KW W900L short on power

I was gonna say the fuel filter may be clogged but you said you changed it. Hmmm

 

What year is your W9 and what motor does it have....?

 

You mean that's important and germaine?

Bet it's got an 18 speed and 24" hoops also.

 

If the check engine light is coming on then it should indeed have an associated code...

 

need more info . On my KW 900 , the water separator is closer to the firewall , than the steering shaft.
If you have an ISX engine , there are a multitude of reasons possible for what you've described.
Oh, is the radiator full? Oil? These not being topped off can sometimes cause this to happen.

 

What a helpful and related reply that was huh?

 

Yup. Oh, well !

 

Sounds like water in your fuel source , buy a tube of Kolor Kut. I'm not spelling it wrong that's how it's spelled. Put a little on a rubber hose and stick it into your tanks to see if you have water in your diesel. I would try to rule that out as a possible cause before going into engine. Low water in reservoir can also cause a code in ISX motors. Not sure if you have a DPF motor ? That could be a possible problem if your not getting a proper regen or your muffler is clogged and needs to be cleaned in a machine. Could be too much back pressure. Let us know how you make out. Good luck kid.