This is my first post to the group, so please take it easy on the "newbie"!!

My 1998 T5 (Auto) "check engine light" has come on/off intermittently ( for 2-3 days, off for 5, back on for 3, etc...)for a 3 week period.No other symptoms (i.e loss of power, etc..) to cause any alarm, so I've been driving it as if it's not even there....

I finally got around to taking to "my" local Swedish wrench here in So CAL. who found an error code that he couldn't identify (not in the service manual, and he had never seen it before in 25 years of wrenching!!)--only that it was some sort of barometric pressure/ altitude sensor.

This fellow has always been very kind, resetting my "service" light and other minor things for free, so I gave him a few days and called him back today.
He now says this sensor is located on the lower front of the car, and is probably going bad ( or already is?)....

Any ideas/ opinions confirming this? And what should the replacement price be? Can I change it out myself, or just let him deal with it, since it appears to be a rather obscure problem.....it is NOT an o2 sensor issue, according to him, and the car runs as well as before, although I'd like to get better gas mileage (but I'll save that for a future post)

Thanks in advance,
HB