[SoCal LS-L]

Originally Posted by dcarrb

Twenty two is a good number. I started logging mileage closely when fuel prices spiked here in the wake of hurricane Katrina, and my average in both cars is 21-and-change. Most of my driving is pure grocery gettin'. Road trips come in consistently at 27-29 mpg.

Getting back to the topic, I'd disconnect the battery overnight, drive for awhile, record the mileage scrupulously, and see how it looks.

Once I got a brief flicker of a CEL with an accompanying oxygen sensor code, did nothing, and the car probably runs better now than it did back then.

dcb

+1 on this point. Have you done any underhood work recently? A disconnected intake tube hose causing vacuum leak?

What brand of O2 sensor did you buy?