2013 Freightliner Cascadia w 2250 cummins

[flatbed94kid]

My truck has no power to it it lags but it does pull the loads a week ago I had my clutch replaced in it. The fuel pump I do not believe has been updated and I will get that done and I wonder if that may help increase my pulling power? Also planning on changing my IMAP sensor, Delta P sensor, and those other sensors with it as well as cleaning my EGR. Yeah this fuel mileage is killing me only 5 to 6 .30 MPGs besides my driving habits I know there's something going on. Has anyone dealt with this before? What did you do to fix it?