Great topic. How about specifying WHICH of the ECU ground locations you
know to be the best one to use.

Mark

Steve Delanty wrote:
> ....
> A 4-wire O2 sensor, with the ground connected to the same location
> as the ECU ground would eliminate O2 problems caused by
> slight (or sometimes not so slight as I found out) voltage differences
> between engine and chassis.
>