My '97 impreza 2.2L outback has a strange problem. When I take it to the mountains, winter or summer, over 4000 feet, the check engine light comes on. When I return to the lowlands and drive around for a couple of weeks, the check engine light turns off. Any ideas?

Have you had the codes pulled to see what code the ECU was actually throwing?

 

It might be a barometric sensor....but I'd have the codes pulled to check. Autozone will do it for free.

I've been lazy and have not had the codes checked. I was sorta hoping that somebody would just tell me it was the widget. I'll have the codes checked and report back when done