My VW Beetle is a TDI. It ate a lifter at 128K miles and destroyed the engine. Cam issues are very common as are other failures. They can be kept reliable but it costs money. I just got mine back running after almost 1 year, mainly because I wanted to address problems and get some good prices on the parts.

Go to the TDI forum and read up on it. It is a great place !! Like this site as well.

Good luck with the Ranger !!