I have a 2002 impreza sti with 81k miles on the clock. When cold its running really bad, i have to keep revs up or it just stalls on me, then it takes i while to re-start it. When its warmed up it doesnt cut out but still doesnt run right. Ive had it in garage and machine said misfires on 1 2 and 3. Oil,plugs, filter, coils changed and it still the same. Plugged it back in a it then said just missing on 1, engine light went off for 3 miles. Now its back on. Is this a common fault/what would you look at next?

Ive had 7 impreza's and never had anything wrong, engine sounds fine and isnt knocking in any way.

 

compression check?

 

Last time I had idling problems on my bug it was the ICVS playing up.......I've forgotten how much it was but £280 rings a bell

Shaun

 

mass air flow sensor as well