Can anyone recommend a good diesel shop in the Harrisburg Pennsylvania area? I need to have the timing checked/advanced and the usual pump tests done for some milage issues. I'd love to do it myself as you all have laid out what has to be done to increase power and economy, but getting the time is just impossible for me. There is a Cummins service center here but I'm not sure if they will advance the timing beyond 13. 5 (I think) listed on the engine tag. How does timing slip anyhow? Thanks for the advice.