Mb426

I have a 99 Impreza thats completely stock and I've been having some idle issues lately. Had a look under the bonnet earlier with no real idea as to where to look first. The car when cold starts up at about 2500 rpm and warm about 1500 and when idle it goes up and down constantly. I found out that the throttle cable was wound up a bit too much so i lossened it and it went back down to its normal idle for a little while. Then it started again, but this time it idled at 1500 and went up and down. I noticed the throttle anchor wasnt completely touching the metal rod that stops it I dont know if thats the issue? If so then how can i fix that and if it isnt that what could be causing this rough idle? I have been advised to clean the throttlebody but i havent gotten around to that yet,

No modifications at all other than an exhaust including the manifold not sure if that would make a difference? And when I filled it I put in just the standard petrol that goes in and I believe it’s 95 octane.

I’ve just bought a 1999 Impreza Turbo and recently I’m having some issues with idling. On cold start it seems to be somewhat fine however on a new tank of petrol I’ve noticed either misfire issues or some sort of idle problem. The car when I clutch in shoots up to a steady 3k RPM and idle it stands from 2.5 to 1k rpm. Just looking for a little bit of help I’m hoping it’s maybe a spark plug that is shot. Could it be a sensor issue a compression problem or anything else any tips or guidance would be greatly appreciated as I’m a new member thanks for your time.