L3901 starts fine but runs very rough and wont rev

[matR]

This problem just started on my 2016 L3901 (HST) that has very few hours (~120). It runs very rough, wont rev above 1200, and is producing a lot of black choking exhaust.
I assume this is a fuel problem? I checked the air filter, cleaned out fuel trap - no difference. Assume next step would be to replace fuel filter?
Any other things I should check?

thanks

 

[North Idaho Wolfman]

Smell the fuel, smell like gasoline?

If it's not a fuel contamination issue, it's a fuel delivery issue.
I would say you have a failed injector.
Not something you can work on on your own, your going to need to take it to a dealer to get it fixed.

Don't run it like it is, as you will seriously damage the emissions equipment, if that hasn't happened already!