I have a 1998 Outback. I just changed the plugs and the PCV valve and cleaned the throttle body... now it's idling at 2200rpm (normal 600-800rpm)! What did I do that might have caused this to happen? From what I've read it looks like there's no way to manually adjust the idle speed on this model. Any suggestions?

sounds like a major vaccum leak,check all the hoses you had off.maybe one is still off or maybe a bad line.

sounds like a major vaccum leak,check all the hoses you had off.maybe one is still off or maybe a bad line.

A reply on another forum suggested that it might just be the ECU readjusting to new parts after having disconnected the battery, and that it should recalibrate itself after a couple of days. What's your take on this?

ive had a high idle for quite some time but if i let it just sit and idle for a minute or two it seems to drop to normal levals

Here's what I have so far...

1) A Subaru dealer told me that this is NOT a computer issue, contrary to what came up on another forum.

2) Suspicious that the plugs might have been the problem, I put the old plugs back in... same problem: still idling at 2000-2500rpm. It does not go down, even after sitting at idle for several minutes, or after driving for some time.

3) Of the possibilities listed so far, that leaves a vacuum leak as the other possibility. I have checked all hoses... everything appears to be in place. What else can the home mechanic do to diagnose and/or repair in this situation?

 

These are seemingly innocuous repairs that I've performed multiple times on other vehicles in the past... strange that this one should go so wrong...?