Very slightly uneven idle - maf and 02 sensor fine, other possible causes.
02 August 2008, 10:21 AM
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Very slightly uneven idle - maf and 02 sensor fine, other possible causes.
Reently had a failing 02 sensor changed on my MY99 which improved things no end, but it can still be a little "lumpy" - the revs drop ever so slightly and then pick up; thought I could detect a intermitent very light popping sound from the exhaust that coincides with the very slight frop in revs too. It's certainly nothing severe, but just discernable. The MAF sensor was fine when the diagnostics were run, so I'm wondering what other factors might be responsible. Suggestions welcome.
Ns04
Ns04
It's been blanked off.
02 August 2008, 11:07 AM
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Dude,
I'm having the same problem in my2002 STi. I've put it down to the recent hot weather but also I'm going to change my panel filter back over from the Green to the TSL Grp N one I have in there. Thinking maybe a little bit of oil has made contact with the MAF but will test it and see.
Steve
I'm having the same problem in my2002 STi. I've put it down to the recent hot weather but also I'm going to change my panel filter back over from the Green to the TSL Grp N one I have in there. Thinking maybe a little bit of oil has made contact with the MAF but will test it and see.
Steve
02 August 2008, 11:09 AM
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I agree, try a new MAF, better safe than sorry. If stil the same, it's MY99, the spare "new MAF wont be wasted 
a dubious possiblity, the Idle control valve (ICV) but when failing normally causes stalling but maybe worth checking, think there is one on MY99
Tony
a dubious possiblity, the Idle control valve (ICV) but when failing normally causes stalling but maybe worth checking, think there is one on MY99
Tony
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02 August 2008, 11:56 AM
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Some parts dont throw a CEL untill completely fubared! Mafs are a good example.
Will take it back to the garage and have the maf voltage checked again to be safe.
Ns04
Will take it back to the garage and have the maf voltage checked again to be safe.
Ns04
02 August 2008, 12:51 PM
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im going for the i.c.v. on this one too. because i had the exact same thing in my old my99 scoob. changed the 02 sensor and m.a.f. sensor too and only a little better. the worst lumpyness was from cold, the car was horrid to drive for a while until warm. a warning light doesnt necessarily come on either... mine didnt and the i.c.v. was fubared.
03 August 2008, 03:57 PM
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https://www.scoobynet.com/general-te...ing-p1507.html
https://www.scoobynet.com/general-te...rol-valve.html
There was some thread with Pic's and instruction on it but cant find them
Tony
https://www.scoobynet.com/general-te...rol-valve.html
There was some thread with Pic's and instruction on it but cant find them
Tony
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