Originally Posted by 9krpmrx8

I tested our Rotary Diagnostics tester, carbon8's TR-1, and a Mazda tester (local member is a dealer tech) all on my engine back to back and there were significant differences but all were fairly close. But if you engine is borderline, one tester could put you below the line and one could put you above. But if you are borderline it is rebuild time as afar as I am concerned.