Hi List! I've heard that one shouldn't attempt to measure the voltage of the oxygen sensor, since even the small resistance of the voltmeter can seriously change the sensor's output. Is that true? Aleksander Mierzwa Warsaw, Poland mailto:alex@matrix.com.pl 87 Audi 5000CS turbo (mine) 88 Renault Medallion wagon (mom's) 91 mountain bike (just in case both cars broke at the same time :-)