MY00, std (no mods) 23k miles,
seems to happen more when engine is hot, rpm drops to about 300 then hunts a few times, it does level off again at about 850. Car also seems to have lost a bit of it's go, it's always run on Optimax, but as a rule doesn't get many long journeys. Plugs are about 2 years old now and being changed next week, but could the idling be MAF or another sensor related ??

Ian

 

Replace your MAF

 

could be idle control valve??

 

I'd still replace the MAF if it's the original.

 

It's going in for a service next week (Subaru main dealer - warranty etc), will they be able to tell which it is by plugging it in to the diagnostics machine ?

Ian

 

My money would be on either the MAF or Lambda sensor (or both), either will cause this. Mine both went at about 31k miles.

 

When the MAF or Lambda fail they often do so very gradually, so the ECU gradually compensates over time. If the garage does an ECU reset, it'll likely show up a fault code a few hours/days later as the ECU is re-learning its settigns and detects the readings are way off what they should be.

When my MAF was replaced the ECU was reset, that caused the Lambda sensor failure to appear a few days later.

 

Thanks for the pointers chaps, I'm assuming I can get these changed under warranty, but what is the cost of them ? just so I've got some idea when the dealer starts to make excuses .

Ian

 

Not sure about Warranty but I'd push for it. If they try to charge you for the MAF they will most likely try and charge for the full housing and sensor @ about £320. However the sensor can be bought by itself for about £72.

 

Yup, i had both my MAF (the whole thing - sensor and housing) and Lambda sensor replaced under warranty. They cost more than 1 years warraty did!

 

Only some Subaru Dealers only Stock the £72 one

Common fault on the MY98-00 MAF's to go down not long after servicing. Some Sh1te gets dislodged during filter checking replacement and contaminates the MAF

Also if fitted with a non STD Filter which has to Oil sprayed warranty on MAF is VIOD. IMHO

Tony

 

i had a dodgy connection on the throttle postition sensor. altho that showed up as flashing on the led fault finder on the dash.