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.

Happy Trails,

Greg Potts
1973/74/79 Westfakia "Bob the Tomato"
1987 Wolfsburg Weekender Hardtop
www.busesofthecorn.com
www.pottsfamily.ca

Matthew Snook wrote:
> How often should we go through all that stuff?  My mileage was right around
> 20 as long as I drove conservatively.  Now my best is 18.5 average, probably
> for the last 2000 miles.  Last tuneup was a year ago, I don't know if Mike
> put in an O2 sensor at that time.
>
> Matt
>
>
> -----Original Message-----
> From: Greg Potts
> Subject: Re: Reduced Mileage
>
> ... I know my fuel economy is down since the summer time but I figure I also
> have other  contributing factors to blame as I haven't replaced any of the
> ignition components or the O2 sensor since I got the van last April...
>