Bill Hambone

It has 188,000 miles or so. I bought the car a year and half ago from a guy who rebuilt the engine. I guess that was the last time it was tuned up. How often do spark plugs need to be replaced? I think they are less than two years old.

For the past few months, the check engine light on my Outback wagon has been coming on. It stays on for a couple of days and then turns off for a couple of days. I got my oil changed yesterday, and they checked the codes for me. Apparently my knock sensor is failing. I've read some of the threads on this, and I will attempt to replace this myself. I'm wondering if this could be affecting my mileage? I figure I've been getting about 16 mpg for a while. This seems to be pretty bad. The guy at Oil Can Henry's also thought I needed a new fuel filter. Of course they want to upsell me as much as possible, but I figure I should attempt to change that as well. Should I check my spark plugs too?