Well, of your two options, I sure hope it's just an O2 sensor.  Otherwise it
means rebuilding the engine, correct?  I really don't know how many miles
are on the engine.  The documentation is...spotty.  The van has about
260-70k miles - how much on this engine?  I don't know.  But the fuel
mileage has only dropped in the last 2000 miles or so, before that I could
pull 20 out of it by driving right and if there was no headwind in the
gorge.  I'm headed down the gorge again tonight, and a 10 mile grade out of
Biggs will probably reduce my mileage as well

Matt

-----Original Message-----
From: Greg Potts
Subject: Re: Reduced Mileage

Hi Matt,

I am not really saying that the replacement interval is a year; it's
just that I don't know how long it was before then that the components
were installed.

Once I replace them, then I will know for sure how old they are.

A bad O2 sensor, that can make for a 2-3 MPG drop on its own. But as Ben
said, the seasonal variation in the petrochemical blend they sell as
"gasoline" could also account for a 5% hit on its own...