Greetings.
I have a 1989 760 turbo that has been recently getting only around 15mpg (mixed driving). I like in Pittsburgh, PA (USA). The best I have ever gotten was around 21mpg on the highway. I drive fairly conservatively, use mid-grade or higher gasoline, and recently had the car inspected (no safety issues such as dragging brakes were found).
The car runs well, has plenty of pep when on boost, but stalls a few times in the morning when started.
I'm wondering if my O2 sensor could be crapped out, thus causing a rich fuel mixture. Does this seem likely? I have no problem getting a new one, but the Bosch sensor runs about $150, so I'd prefer something better than a "maybe" before I cough up the cash.
Thanks for any help,
--Dale