Look's like the MAP sensor has failed on my Forester S Turbo MY00 (pretty much the same as an Impreza.
Question is how much do they cost?
Incidentally, the symptoms are / were, total loss of power, then only able to run upto about 3000 rpm before limiting (similar to misfire), trouble code 23 showing (two long flashes then three short flashes on the check engine light) this is MAF or MAP problems according to the service manual. I have measured the MAF output with the ignition on and it is only 1.060 volts, I think it should be 1.1 - 1.2V. Checked the MAF externally, seemed OK, cleaned carefully with isoprop alchohol, still a problem.
Interestingly, sometimes the check engine light will go out for a while. With the engine running a moderate tap with a finger on the MAF housing caused the engine to change speed (measured the output with just the ignition on and tapped the housing, voltage raised to 1.12V, hence the engine speed change).
Off to Ecutek and PE rolling road on Friday so I need to fix it before then! Anyone got a MAF handy?

[Edited by MattRus - 5/1/2002 10:25:44 PM]

 

Sounds like when mine went. No physical evidence of contamination or damage, probably the internal electronic that goes haywire.

What you experience is that your ECU goes into 'limp home' mode,
hence no boost.

Out of curiosity, are you running stock air filter?

-Christer

 

No I have a K&N panel. It's been in for about 20K miles and cleaned carefully once. car has done about 41K miles.
what did the sensor cost?

 

Had the MAP sensor go in my 93 WRX. Being the old type of sensor the local Subaru dealer wanted £200 for a new one!

So decided to try Grade A Subaru Breakers who sent me one off the shelf for £30 - arrived next day.

Take the car to your local dealer to confirm that it is the MAP sensor first (they should be able to swap it for a good one), then try breakers.

 

I had it switch on warranty, since my -00 was registered first late 01 i have another ~2 years of warranty left.

Should be a warranty issue for you?

 

Just replaced the sensor - cost £286 (ouch!). Apparently in Greece (see other thread on MAF failure) they are now selling just the sensor, which is alot cheaper about 90Euros!
Apparently according to the parts department I purchased mine from, they sell quite a few, enough to have several in stock!
Watch out!

 

Does anyone know who manufacturers the MAFs for Subaru? I know Bosch manufacturer them for other vehicles, so it would be ideal if we could bypass subaru and buy from someone else. Especially if they're not willing to just replace the MAF itself.

Stefan

 

Well they're supposed to be selling them, just the sensor in the UK too, according to Muttant_Matt.

 

Sounds like an easy way to make money to me