I have been using the services of this company for over 4-years now and LOVE it. People with diesels should especially take note in regards to the analysis they provide. The reports are detailed, easy to read and as stated they do build upon each analysis to give an overall rating of the engines health. The database they have on each of the diesel engines helps them identify issues particular to the model based upon the thousands of samples they receive. Current cost is $22.50 for a basic analysis(covers ALOT), and you usually have results within a weeks time.
Have truck: 2004 F350 4x4 Lariat Crew Cab 6.0 Diesel(updated motor), gauges, RHINO Liner, Husky Floor Liners, DPPI Turbo Back Dual exhaust, AirRaid intake
2009 Crossroads Cruiser CT31RL..loaded with options