Do the multimeter thing. Disconnect the O2 sensor lead from everything else and just connect the multimeter to it.
How's your ground path from the exhaust (O2 sensor ground) to your O2 instrument ground?

Finn

Russell Duffy wrote:

Russell,  I tried the Bosch11027 about a year ago. It fouled quickly and I had the same kind of symptoms as you.  I replaced it with a Bosch 12013, single wire, which has functioned okay so far.  Using mogas only so far.

Regards,

Tommy<>< 

 

 

Thanks.  I'll keep that in mind, but it's the same sensor that Tracy and Finn are using, so it can't be all bad.

 

Rusty