AKDave90

Hey y'all, So I have a '93 Legacy, and it has recently been doing this funky idle dive. When warm and idling, the RPMs hover comfortably around 500. While driving (most often when engine braking), when I depress the clutch either to coast or shift, the RPMs dive down close to 0 then fluctuate between 500 and 0 for a few seconds before settling in at 500 or a little less. It doesn't always do this, and it has no fluctuations when idling at a stop light. This problem was more of a curiosity until the engine actually died on me yesterday. I was camping around 5,600 ft at the end of a small mountain road. The car restarted fine, but as I descended (using the engine to brake), the diving idle kept happening but without killing the engine completely. As I descended back into the city, the problem seemed to return to its normal "once in a while" standard. Could it have something to do with altitude? I want to get this fixed b/c I need to drive up to Alaska in January, and I don't want to get stuck somewhere. Thanks for any help you can give. Dave