hey guys i'm experiencing some issue s with my car. from what i've read it's a fairly common problem, basically every time i pull up to a red light or come to a complete stop and put my clutch in my rev s drop right down, sometime s to 0 and the car will just stall. im not having any other problems, the car starts and idles fine, after researching i thought it was my afm, $260 later i put in a new one and still same problem any idea's?

got any large air leaks? check all the intake piping after the air flow meter

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Version 6 STI

It's usually a non standard blow off valve opening at idle, leaking air. Put it back to standard plumb back and see what it's like.

thanks for the quick reply's, i'll give it a check over for leaks, and yes i have just fitted an aftermarket hks bov, but this problem existed a good few months before i fitted this. Though you gave me and idea, now that i have a new afm i might fit my stock plumback again and see if that makes a difference, fingers crossed because i feel i just wasted $260, as i said though it idles fine it's only when pulling up to a stop the revs dip

always good to have a spare "known good" AFM. Either that or I'm sure somebody will buy your spare if you don't want to hang onto it.
Have you checked for any error codes?
Good luck with the fault finding otherwise.

yeh thats a good point, since they often fail it probably is a good idea to just hang on to it. How do i check for error codes? doesn't the engine check light need to be on to do this ? maybe i should just take it in to subaru

My car does exactly the same thing. I've got it booked in at rms next week so hopefully they can help me diagnose it. I'll tell you what they say, if you can wait until next week. Just drive off boost for a while.

check 02 sensor also.

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Signarape!

How can you check the O2 sensor? and also where is it exactly?

on my99 its in the dump pipe right behind the turbo, connect a mulimeter to earth and to the signal wire off the back of the sensor (either white or white with black stripe.. can't remember) you should see the voltage fluctuating between 0 and 1v, if it just sits at constant voltage your o2 sensor is dead