My 04' STi has just recently started giving me a very strange problem. Here it is. When I come to a complete stop with the clutch pedal engaged, the engine RPM's go to normal idle RPM then the RPM's shoot up to around 1,000 to 1,500 for a few seconds before returning to normal idle RPM again. It does it worse with the A/C off. I also notice that sometimes after I shut the car off and start it back up ( like at a gas station ), the engine runs very rough and is burning rich. The car only does it for a second before clearing up. Neither of these problems triggers the check engine light or effects the performance of the car in any way. It's just anoying to have my RPM's hunt at 1,000-1,500 when I stop at a light or whatever.

 

Are you still under warranty? If so I'd take it to the dealer. If not, I wouldnt listen to me and wait for someone else to post.

 

Any mods done to your car?

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0==WW==0
"…axles of evil…" - george w. bush

 

I have a Cobb catted downpipe, AccessPort running Stage2/91Oct, RS*R catback, and a K&N drop in air filter.

 

sounds like maybe a problem with the map from the accessport. try changing maps and see if theat fixes it

 

maybe u need to change your spark plugs i did mine yesterday and idle is smooth now.