Need help diagnosing hard start/rough idle issue

[fLaried]

I was driving back from work and around 7 minutes before I got home, I realized that Im not getting alot of power even though im pressing the pedal down hard. I realized my car wont go over 2.5k rpm and it shifts slow all the way to 6th gear. I pull over and listen to my car to see if its sounding off and it sounds a little bit different but at the moment I thought it was fine so I turned off the car and tried to start again and it hesitated for a good second (usually mine starts right up) and then same thing Im driving low power and car wont go over 2.5k rpm and it shifts slowly. I got home and checked for codes and, I didnt have any showing no glowplug light no check engine. I thought it was a cp4 pump issue and checked and I didnt have metal shavings in the filter or the pump itself so I need help diagnosing this issue since I dont have any codes and not sure exactly what the problem is

 

[ZippyNH]

When was the fuel filter last charged?
Low power... limited RPM....might have gotten some wet fuel ...or simply finely got bad enough to make a difference
Plus you car type and year kinda helps...

 

[fLaried]

When was the fuel filter last charged?
Low power... limited RPM....might have gotten some wet fuel ...or simply finely got bad enough to make a difference

2k miles a go I also checked the fuel filter as well and it was clean with diesel.

 

[ZippyNH]

My next guess would be a turbo problem... mostly a shot in the dark
Tailpipes clean?
What year? You might get more answers in the model specific forum