Well on my 2001 K3500 with 75,000 miles I decided to add a fuel (lift)pump and I can say the results were excellent. I had the same problems with my Topkick (now also fixed) with a Cat engine so I got to the store and bought a '98 GM diesel liftpump made by Carter then removed the fuel line from the tank hooked it all up with a relay and a aftermarket filter. And the results were a much smoother idle and power where sometimes I would step on the throttle and it would hesitate or just be dog tired. I can also say I found the quick connections on the hoses to be quite loose so if you are having problems you should at least consider changing the supply hoses at the tank and engine if you have an older truck, you can get the release tools from KD tools and you can get at the top of the fuel tank by just bending over the aluminum shroud and reaching in. A new hose would give you new o-rings and seals and would help a host of problems I see on this site that are dogging owners with stalling and power issues. Like I said on my Topkick I spent about 3500+ dollars - twice changed the injectors 3 times tuned up replaced most of the fuel lines and with not a visible leak , always stalled after startup (hot or cold) and sometimes almost no power I was baffled - I added the 125 dollar fuel pump and not a problem since and that was 2 years and 15,000 miles ago.