... measured at the leads on the frequency valve. Getting a fluctuating 12-20%. So I decided not to mess with the mixture, since the voltage out of the sensor seemed about right.

Got a smog test today and passed! A little close on HC at idle (183 ppm with a limit of 220), but otherwise fine. The tech was surprised.

So thanks again for the advice on this.

__________________
Chuck Taylor
Falls Church VA
'66 200, '66 230SL, '96 SL500. Sold: '81 380SL, '86 300E, '72 250C, '95 C220, 3 '84 280SL's '90 420SEL, '72 280SE, '73 280C, '78 280SE, '70 280SL, '77 450SL, '85 380SL, '87 560SL, '85 380SL, '72 350SL, '96 S500 Coupe