very rough idle MY05 GT

[BlackDuck]

Suffering very rough idle and poor fuel usage. Subaru have changed AF sensor with little change. They have suggested O/S AVCS is sticking on. Has anyone else had similar and what was the fix?

[3rspecb]

A mate had similar problems with his 2ltr GT and on his last service, Subaru (docklands in melbourne) performed an injector clean and it fixed his problems.

[ultrablue]

i have the bad idle but good fuel usage for me its the injectors one day i will replace them

[BlackDuck]

Thanks - looks like the injector clean is the best next step. We will see what happens

[ultrablue]

i had my injectors cleaned and it only took 3000km for it too come back i have heard if your 02 sensor goes you get poor fuel consumption

[suff]

I would be looking at the following:


Air Filter (ESP if you have an oiled filter)
Injectors (try a standard "bottle" cleaner first)
AFM (Clean it with electrical contact cleaner)
Upper 02 sensor (behind your TMIC)
Injectors

Last two should be diagnosed by a mechanic, but the top three will be highly likely the cause and will cost you very little to check / clean

[541NTT]

I would be looking at the following:


Air Filter (ESP if you have an oiled filter)
Injectors (try a standard "bottle" cleaner first)
AFM (Clean it with electrical contact cleaner)
Upper 02 sensor (behind your TMIC)
Injectors

Last two should be diagnosed by a mechanic, but the top three will be highly likely the cause and will cost you very little to check / clean

i looked at all these things when this happenned to my 04gt- had it at the works mechanics for a week and he changed alot of things and couldnt get it smoothing out- then got the car back, took it to boxer service on the north side of bris- they had the car for 1 hour and had it fixed, turned out to be a tiny bit of gunk stuck in the main valve for the vvti (i think that was it) so the valve wouldnt seat properly.

my advice is to just take it to the mob close to you who deal with engines all day everyday and have a history of workin on the boxers, subaru refresh mechanics all the time and for a mechanic to come from a straight 4cyl to a boxer its apparently a different world.

[qship]

Also look for a vacuum leak in the hoses running off the manifold.

[dewess99]

I also had rough idle and stalling on my 04 JDM Legacy GT.
I found out that the sleeve inside the Oil flow control solenoid valve (OCV) belonging to LH intake camshaft was stuck. The advance was locked at 53 degree according to data logging with Romraider logger.
I dissasemble the OCV and just loosened the sleeve with a screew driver and now the car idle perfekt again

/Dan

[DJC]

I suffered rough idle as well on my 04 GT. Was diagnosed as my upper O2 sensor as previously mentioned by suff. The fix has also helped drastically with fuel consumption.

[gt2nv]

hey guys just got my 04 gt and seeming to have the idle problem and bad fuel consumption would u guys know how much i can approximately expect to pay to get it fixed?

[tangcla]

hey guys just got my 04 gt and seeming to have the idle problem and bad fuel consumption would u guys know how much i can approximately expect to pay to get it fixed?

$480 or $520 from Subaru, fitted. Comes with one year parts warranty, too.

[gt2nv]

thanx for that. what do you think it could be it seams like something is misfiring when in park or neutral, makes the car shudder abit?

[Q]

thanx for that. what do you think it could be it seams like something is misfiring when in park or neutral, makes the car shudder abit?

I'd be betting on the injectors being the problem. There is a set of different injectors that Subaru can supply to cure this problem (I got mine replaced under warranty to fix this issue). How many klms have you done? I'd get them cleaned first professionally and that should fix the problem for a while. Then a new set of injectors could be on the cards or you can put up with the erratic idle

[gt2nv]

its done 106k but just had major service done approx 3k ago is it a serious problem or do you think its something minor like getting it cleaned?