erractic idling Subaru Impreza

[Harryburgundy]

Hopefully there are some mechnics out here who might be able to help.

I have a low mileage 1996 Subaru Impreza Sport 2.0 non-turbo.

Drives very well but recently, on occasion the idle runs too fast. It normally is steady as a rock at 700rpm but occaiaionally idles at 1200-2000.

I checked the auto dyognistics and no faults are showing. Tried the dyognistics when the engine was running high too. Subaru people say rarely would it be the maf sensor... Any suggestions?

 

[velofrog]

Re:

a failing/failed lambda/O2 sensor would give an erratic idle, or a gummed up inlet butterfly

 

[Neil]

Re: erractic idling Subaru Imprezza

IACV playing up / sticking?

 

[Harryburgundy]

Re: erractic idling Subaru Imprezza

IACV playing up / sticking?

What's that?

By O2 sensor do you mean the mass air flow sensor velo?

I'm not great with car engines.

And apologies for all the typos!

 

[velofrog]

Re:

here you go carl....

http://forums.nasioc.com/forums/showthread.php?t=781242

O2/lambda sensor is a probe that monitors air/fuel mixture for the catalytic converter to keep the emissions in check

 

[Neil]

Re: erractic idling Subaru Imprezza

IACV playing up / sticking?

What's that?

Idle Air Control Valve, the jasper that maintains (or should) idle speed correctly, in pre electronic throttles (and even they often have a similar auxiliary air valve).

Reason I suggested it is because I think you said there were no error codes logged - which often happens when they play up, whereas failing, or out of tolerance sensors often do.

edit: also check ignition wires and coil.

 

[Harryburgundy]

Re:

Many thanks both

 

[T'boo Ted]

Re: erractic idling Subaru Imprezza

blah blah i'll jhust talk crap.

 

[Harryburgundy]

Re: erractic idling Subaru Imprezza

blah blah i'll jhust talk crap.

???

 

[highlandsflyer]

Re:

I am sure you have found all the Subaru forums, they are everywhere! In fact the number of conflicting 'expert' opinions on any problem you might have can be rather overwhelming.

Find it easier to stick to the perspective of basic mechanics rather than listen to a lot of the advice given by people who may have driven Subarus for years but aren't actually imbued with a knowledge of basic spannering. You get the impression a lot of these people have spent years sucking it and seeing, and then fix on routine responses based only on their personal knowledge.

My latest Forester has a wee hole in the cat. This is causing it to hunt a little on idle.

I don't know if that is true, but until I get the new one I have ordered and fit it I won't know.

Eliminate all the cheapest options first is all the advice I would offer.

So indeed cleaning everything you can get to makes sense, and depending on how long it is since you gave her a good servicing new plugs, leads, blah, blah, blah would be of no harm at all.

I think I am always going to have a Subaru. I mean until I expire.

Is that fanatical?