Idle surge

[fl440]

Hi guys,

Just bought an 2006 impreza 2.0l 4wd.

Just a small problem thats started. Once the car is hot the idle tends to surge up and down. Only seems to happen once warm.
50,000km on it.
No CEL and no fault codes showing.

Any ideas most appreciated
Cheers

[KronosPerformance]

Just to clarify....are you sure you have a 2006? 2006s dont have 2.0 motors

[MakeItRoar]

More info would be appreciated, a rough idle could be the idle air control valve, bad grounding, a bad MAF, boost vacuum leak, or a slough of other things. Mods? How much does it surge? Like 100-200K or like 500-700K?

[teflon_jones]

Where are you located? How many km's have you driven the car? How many km's after you bought it did this start, and how many km's has it been happening for?

Have you tried basic stuff like cleaning your MAF, ensuring your air filter is clean, inspecting the hoses, etc?

More info would be appreciated, a rough idle could be the idle air control valve, bad grounding, a bad MAF, boost vacuum leak, or a slough of other things. Mods? How much does it surge? Like 100-200K or like 500-700K?

Wow if the car is surging even 100,000-200,000 RPM I'd be running like hell away from that car, never mind 500,000-700,000 RPM!!!!!!!

[fl440]

Where are you located? How many km's have you driven the car? How many km's after you bought it did this start, and how many km's has it been happening for?

Have you tried basic stuff like cleaning your MAF, ensuring your air filter is clean, inspecting the hoses, etc?
Wow if the car is surging even 100,000-200,000 RPM I'd be running like hell away from that car, never mind 500,000-700,000 RPM!!!!!!!

Hi sorry,
Wasnt too sure how much info you would need.

Its done 52,000km and probably 2000km since we bought it. The problem has started in the last 300-500km and i havent done anything yet as i thought i would see your thoughts.
When it surges it probably blips 100-200 rpm and you can see the lights dimming and brightening on the dash as it does it. Hope this helps

Cheers
Mark

[MakeItRoar]

Wow if the car is surging even 100,000-200,000 RPM I'd be running like hell away from that car, never mind 500,000-700,000 RPM!!!!!!!

Haha wow, didn't even realize I added K's...

[johnny333]

I'm not an expert by any means with these cars, but I posted almost the exact same problem a few days ago. A couple of the guys on here told me it was probably my spark plugs. I changed them, problem went away. NOW, I have more miles on my car, (74k) so it WAS due for plugs, where yours is close to the window to change them but not quite there yet. However, it might be worth the few bucks and 2-3 hours of labor to just do them and see. If nothing else, your tune-up is done early! Hope this helps!

[johnny333]

P.S. mine WAS ALSO only when warm and would jump around 100-200 rpm.

[mycologist]

Hi sorry,
Wasnt too sure how much info you would need.

Its done 52,000km and probably 2000km since we bought it. The problem has started in the last 300-500km and i havent done anything yet as i thought i would see your thoughts.
When it surges it probably blips 100-200 rpm and you can see the lights dimming and brightening on the dash as it does it. Hope this helps

Cheers
Mark

Did you just recently start using AC or defrost?

[fl440]

Did you just recently start using AC or defrost?

Nope, no AC use or anthing.

Seems to run fine to warm up, then turn car off after a Period of driving. Then start it up again say 10-45 mins later and it surges 100-300rpm tops.

Just had e spark plugs changed and all the throttle body, manifold cleaned.....