06 2500 Mega Cab Questions

Had the truck now for about a week and notice a couple things. Not sure as to how to go about explain the issue but I'll do the best I can. Truck seems to run fine or as best I can tell it runs fine, new to the diesel scene. Truck runs up to speed (70mph) but seem to take a bit to get there, when I step into it to pass on the interstate or going up a hill and need to speed up, truck will drop down out of over drive but will not build up speed. Same thing if it drops down to passing gear around 45-50, truck just wont build up any speed in a hurry. Its like the truck will down shift but still just hang out at the same speed. It will eventually get back up to speed on the interstate but not in any hurry. Also haven't really pushed the truck but 70-75 seems to be just about all I can get out of it. The trans seems to shift pretty hard, like it has a shift kit in it but not sure yet what has been done to the truck other than a few engine mods that I can tell, S&B CAI and MBRP cat back 5" exhaust, use to be a turbo back to dealer cut into it to put a cat back on it to sell me, not happy about that.

QUESTIONS:

Could this be a issue with Transducer/Pressure Solenoid in the trans? Would this keep it from build up speed? I've been reading about the Borg Warner replacements and going to looking into this.

If this is not the problem then maybe the lift pump? There is no smoke from the truck, fuel mileage seem to be good, turbo seems to be spooling up, seen boost psi around 25-30. I have the EGT, Boost and Trans temp ISSO pillar gauges. Highest I've seen on the EGT is around 12-1400 but at 70mph its usually around 6-800.

I noticed that I have a two piece exhaust manifold and I think its a BD. It has and diamond with BD inside the diamond stamped on the manifold?

How would I go about checking the injectors to see if they are stock or upgraded?

There has been some money spent on this truck, 6" Lift, XD Series Spy 20" wheels, Nitto Trail Grappler 295/65/20 tires, Pioneer AVIC-Z130BT Stereo, Alpine Amp, Viper Alarm/Remote start and the other mods I mentioned above so I can't help but think there may be more than what I see or even know what I'm looking at. There was at one time a amp and sub woofer's behind the rear seat, the wires are still there and by the outline of where the amp was mounted, it was huge. Took up most of the back wall and the power and ground cable are almost the size of battery cables. Theres also an adjustment knob to control the sub woofer's still wire under the dash. So who knows what all has been done other than the guy that did all the work and I have know idea who that was.

Any help or advice would be more than appreciated.

Man, I've got 45 looks here and posted this same question in two different forum and no one has any insight on this, hum.


Thanks
Tim