In the two years I've owned my gsr, I've never replaced the pcv valve. I was wondering, can it really have that big of an effect on your gas mileage? I'm getting pretty bad mileage and I'm hoping this is a big reason. Also, is it very hard to get to swap it out?

 

The PCV valve has little to no affect on gas mileage.

It is easy to get to and swap out (assuming the hoses haven't become brittle and fused to it or the manifold) but it only needs to be done if it doesn't function properly anymore. Clamp the hose with pliers while the engine is running and if you hear a click, it is fine. Otherwise, it needs to be replaced.

The PCV valve only needs to be inspected every 60k miles, according to the maintenence schedule.

 

Thanks for the info Schmoo. Considering how the previous owner took care of the car (or, didn't), it wouldn't surprise if it's never been replaced. I'll check it out tomorrow and see if it's still working ok.