WRX - Slight splutter when accelerating
 

My 51 plate WRX has just done 25k miles which is pretty low for it's age but I have noticed a slight performance 'murmer' at about 2.5-3k rpm's. Sometimes it is more of a splutter but only occasionally, normally it just feels a bit reluctant to 'GO!'. Sometimes it occurs again at about 4k rpm's.

A bit vague I know but any ideas?

It hasn't had it's 30k service yet because it had it's 10k service at 4.5k miles and it's 20k service at 17.5k miles.

I'm thinking of booking it in for it's 30k service 5k miles early to see if they can diagnose the problem but want to see if anyone has any suggestions first.

Thanks.

hello again.

I'm no expert but maybe try some simple things:

Are you using Super Unleaded (OptiMax) - I've driven an STi with standard 95 octane fuel in and it did stuff like that.

Try resetting ECU?

Had it had any mods - do you know the history?

I would suggest cleaning the boost solenoid before you do anything else :)

Do a search in the technical forums, you'll see how common it happens. Really easy to clean aswell and someone has posted very accurate instructions for carrying it out.

Anyone mention MAF ?


awaits PLEWIS comment!

The car hasn't been modded at all, totally standard. I'll look at the technical forum for the instructions - thanks for the posts!

I run it off standard 95ron, although I did try 97ron but I have read that it takes ages for the ECU to re-configure itself and to feel the benefit, without having the ECU reset. Will Subaru reset the ECU, apparently not all garages will?

the MY01 ECU will adapt over one tank of Optimax.

Check you boost solenoid as mentioned. Could also be a failing MAF but I suspect the former.

MAF on new age Impreza's... is this still creeping in?

What's a MAF (and more importantly, is it expensive to repair/replace?)

Manifold Airflow Sensor - circa £150 nica if it needs changing (on them classics),

Not read of any going on the new age ones yet... but no doubt someone will post if they have....

Clean the boost solenoid, cleaned mine the other day and it fly's now :)

Is this something you should be doing, even if your car is running apparantly normal?

02 WRX

I didnt think my car was running that bad and i did it and couldnt believe the difference it made

This must be done then, how do i search for the instructions on how to do it?


Cookie

Mass
Air
Flow
Sensor
I'd try the boost solenoid before looking at the MAF. Also take off your plug leads from the coilpacks. Clean the coilpack contacts with very fine emery paper and a touch of WD40 into the leads. This sorted out a similar prob in my MY00 car. MAF is £77 from Subaru by the way...Search on here for the part no. before you buy however. ECU takes 2 tanks tops to adjust to fuel Bob

If you go to general technical cookstar or look at this thread :)

http://bbs.scoobynet.co.uk/showthread.php?t=431447

One of the steps in the boost solenoid cleaning process states:
"Connect green wires under dash"

Can anyone confirm what green wires and where?

Thanks.

The green wires *i think* only relate to the classic (sorry but i haven't done this on my bugeye)

In my experience and talking to others the major cause of an oily boost solenoid is booting the car above 4500 rpm in first gear. I think the oil pressure rises so much that there is seepage into the solenoid.

I will stand corrected though ;)

If your car is "apparently" working fine then dont mess with it. *If it aint broke, dont fix it* :)

thanks for the correct - don't know where i got the 'manifold' bit from.