My truck is having similar problems to the power loss subject below and also white smoke coming out the exhaust when I donshift, and I've read several other messages listing the same kind of problems. I would like to look for air leaks, but don't know where to start. Any help or suggestions would be appreciated.

 

The first thing to do would be to check all the clamps on the air system to make sure they are tight. Then start checking the rubber boots that connect the intercooler pipes. Poke them with your fingers to see if there are any holes. A common trouble spot is where they come close to the fender down by the intercooler, they will often wear through in that area. Also make sure that the intake elbow and manifold plate on the top of the engine are tight.

If you don't find anything, then it's time for a pressure check.

 

even knowing how to do it, it takes a pretty specialized little setup thats not worth your time to build, I just took it to my local Cummins dealer and they charged me a 1/2 hour labor and it was done.

 

I can see getting the inlet system pressure checked (special tool 9022 at the dealer) for a lack of power issue, but that isn't going to have anything to do with a "white smoke" on downshift issue. I would have it scanned to see if an fuel issue DTC's are present.