uk_Mo

Please Please HELP my MY95 WRX Import has recently just started Idling erraticly. I mean the other day I was out for a little run and I nailed it in 1st gear till it hit the limiter and then stopped straight away for traffic lights. but when i was sitting at the lights right after that my car was idleing at 1500 rpm and going up to 2500rpm and back down again. now there are no mods to the engine whatsoever apart from a forgemotor sport dump valve and a boost gauge. I thought maybe the hoses for the boost gauge were leaking so i cable tied them on and they seem to be nice and tight. after cable tieing the hoses it hasnt idled at 1500rpm again instead this time it idles at 1000rpm and then maybe drops to about 500rpm if i turn the engine off when this is happening and start it back up again its fine for a little while then its back again. Please help

Ade_WRX

The usual suspects are the lambda sensor, which i have just changed on my 95WRX or the MAF sensor. Since changing the Lambda sensor I have found a marked improvement. I paid £40 + p&p for a Bosch LS02 sensor.

Hope this helps
Ade

uk_Mo

Hi Ade I just changed the Lambda Sensor 2 weeks ago for its MOT. is there any way of cleaning the MAF sensor or does it have to be replaced?

Thanks for the info

Ade_WRX

Not sure what you could use to clean it, possibly isoproponal alcohol would be the best bet. I think most on this forum would advise to change the sensor but I haven't sourced a price yet. I'm going to a dealer today so i'll price one up and ask if there is anyway of cleaning it.

Ade

scoobyster

My non turbo had exactly the symptoms you describe, it was the idle air control valve at fault. Do a search on IACV and you should find instructions of where to find it on a turbo and how to clean it. However, cleaning only fixed the problem temporarily for me. A new (to me) IACV from a breakers solved the problem for me, although I had to wait weeks for a gasket for it to come from Subaru Japan. In the mean time my throttle position sensor broke too, so don't put it off. I had to replace the valve itself, just the solonoid which controls it wouldn't do.

To check the MAF sensor, when the problem occurs, leave the engine idling and go under the bonnet to unplug the MAF sensor. The engine will stop if it was reading from the (working) MAF, if it was relying on a guesstimate from the ECU it will keep running the same and you need a new MAF. That's what I was told anyway. If you believe it could be your MAF replace it quick as your engine can detonate and go bang if it's running too lean. I put my money on it being your IACV though. Check your ECU diagnostics (connect to black spade connectors under the dash, switch ignition to on, and read the codes from the CEL - instructions here.

Hope that helps.

Ben