[dcb]

Is the mpguino reading high?

If so, then the new number should be 20625 * (61.75/60.00) = 21227

If not, then the new number should be 20625 * (58.25/60.00) = 20023

But it is better to calibrate it with distance, the odo is far more accurate than the speedo usually, and/or next time you are on the hiway a long time use the mile markers to keep your odo honest.

P.S. rmccomiskie, it might help if you record both simultaneously, at cd stereo sampling rate but 8 bit depth. the raw wave format is pretty easy to decypher, don't know about compressed, but having both signals captured at the same time could be something of a rosetta stone for that ECU signal if other VW/Audi groups don't have the answers.