Hi all.Just wondered if you can help out. I have a K&N filter fitted to my 99 wagon & once its warmed up the tickover goes from @ 1000rpm to 200rpm & back & keeps doing this.Also stalls occasionally after gunning it & coming to a rest. I've been told its something to do with the Mass Air Flow on the ECU or something. What can I do to sort this out.Any advice greatly appreciated.

 

K&N Filters use oil, this oil gets transferred onto the MAF Sensor causing the car to feel pissed and do all weird things.
Get rid of the K&N, clean up the MAF Sensor or replace it and then fit a new Air Filter that is MAF Sensor Friendly ( one that doesnt use oil ) Plenty to choose from, just a case of choosing which one.

 

might be your maf

 

thats what happened when my MAF was shafted.

 

OK thanks for those but have taken MAF sensor off & cleaned it & now car won't tickover.DOH! Think I ain't cleaned it properly.Got somebody coming down to have a look so hopefully will get it sorted.

 

The film type MAFs fitted to MY99-00 don't take too well to cleaning. Better to replace it £70 - £80 from your local Subaru dealer. Do an ECU reset after. And get a non-oiled panel filter e.g. STI or OEM Subaru.

Take it easy until you get it sorted. Knacked MAF = DET = Melted Pistons

 

The K&N may not necessarily be to blame.... Oh whats the point - this is SN and the place to be for truths, half truths and down right dodgy information, given out ***** nilly.

F

 

The MAF's die on their own. Replaced mine MY00 with 23,000miles on the clock.
It played up early in the year. New MAF sorted it (approx £72)

 

Easy tiger!

It's possible it wasn't your MAF, but you've now fcuked it by cleaning it...! It could have been lambda sensor, TPS, ICSV, as well as MAF.

Anyway, your first stop it to replace the MAF. Nearest Subaru dealer, part number is 22794AA010 Meter CP-Air Flow.

The K&N shouldn't really cause a problem, unless you've re-oiled it yourself, and gone OTT. But if you want a dry alternative, go for the STi.

Once your new MAF's in place, you can try and sort the idle problem out. A simple test for the lambda sensor is to simply disconnect it, and see if things improve. If you had an AFR gauge, you'd know for certain if it was failing/fcuked (but you haven't, have you?!). You can also reset the ECU using the plugs beneath the steering column, and see how long it takes to flash the all clear, or whether you get a CEL error code.

I doubt if it is TPS or ICSV, but if the above doesn't sort your problem, post back and we'll take it from there.

 

Ah, some sound advice from the Judge!

F

 

 

Thanks for all your posts & advice. The Judge,wow! You are talking to a guy who was brought up with points & condensors so a lot of it as gone over my head but thanks anyway.
Hopefully I will be sorted later today (big thanks to Jeff & co. at Sheffield Subaru Centre who came out to me & tested the offending item).
Hope I'm sorted anyway cos I'm off on me holidays this weekend

 

Have you checked for a CEL code?

 

Problem is now sorted thanks. New MAF seems to have done the trick just going to get hold of a standard airbox now to replace the K & N.

 

Nice one.