I have owned my 01 3500 for 4 years now and know just about everything about them. What am I looking for on the CR motor and are there any specific years to avoid and why?

The only weak spot I know of for the CR series engines is the injectors and the lift pump. Injectors requires super clean fuel 2-3 micron fuel filter. As for engine wise when common rail injectors go out it can do serious piston and cylinder damage with major blow by. The stock lift pumps are weak and can't keep up with the demand volume wise. Sad but true a set of 6 common rail injectors cost more than 1 VP44 injection pump.

Depending on where you get the pump, you can actually get 2 for the price of 6 injectors. I have had good luck with my 03 HO 6speed. It hasnt needed any injectors since I ditched the quad with high rail pressure. Most people say that the 03-early 04 get the best mileage but the 04.5-newer respond more to tuning.

So all- N -all Dodge still didnt learn anything from the first go around with the carter pumps.

So all- N -all Dodge still didnt learn anything from the first go around with the carter pumps.

This is the point of history where the in-tank lift pump was designed and used for all 98.5 and up trucks... (Making matter worse) http://mopar.mopar1973man.com/pdf/IntankPumpExposed.pdf

I guess a AirDog would be the solution? What size would be my next question?

100 or 150 is fine...

100 or 150 is fine...

Or, if you want to keep the OEM FF canister, I'd recommend the Raptor system now. Internal fuel pressure regulator(no return line to the tank) and a proven quality pump...............like the Walbro and AD pumps. If you keep the OEM FF canister, you'd be wise to add a 2 micron secondary filter after the OEM one and before the CP3 fuel pump. Clean fuel is number 1 on the "common rails" because of the pressures the injectors see!!!!

The in-tank pump that started being used in 05, and as a retro for 03-04's, is actually a good pump. They provide all the flow needed for the CP3, even with up to about 100 hp over stock (on a 04.5+ motor). Towing I never see lower than 6 psi and have 3 fuel filters and 4 banjo-bolts in there.. plenty for a CP3. If you upgrade the fuel pump and are sub 500 rwhp I recommend a Raptor and a Liberty canister, no 1/4 tank issues, better filtration possibilities than the filtered AD/FASS and easy install. Other than fuel filtration there really aren't too many HPCR issues. Early 2005 trucks did have a plastic end-capped IC, which don't last long.