I have a MY00 Impreza WRX (U.K Version)with a Dawes and ITG filter and Denso Ik22 plugs as the only mods.

The car has had all these mods for over a year and has wirked great until now.

The car is going to the dealer(Dawes will be removed first ) tomorrow as I am having idling problems with it. It idles up and down +/- 200 RPM, and if reved in neutral it wants to stall before stabilizing at 800 +/- 200 RPM.

The Autometer AFR shows the fuel ratio behaves the same as it did before the idling problem, boost is fine and the car runs perfectly except for the idle issue.

For this reason I tend to think that it is more likely the O2 sensor rather than the MAF sensor.

I will check the filter and box to see if there is any "green gunk" as has been reported on this site by many people.

Does this seem to make sense to anyone out there?

Comments would be appreciated!!

 

I think you've got it covered. If it's not the O2 sensor (most likely I think), then get the dealer to check the throttle position sensor and purge valve.