Yeah i know this old chestnut.On my 2001 type R it idles ok at stand still but say when i pull up at traffic lights the bloody thing stalls!!It's got a Blitz bov
thanks
Dan

 

Got a similar problem that only started this week..a rough idle at standstill, it hunts up and down in the revs and only settles for a few seconds at a time. It feels like a slight misfire as well, from the way that it shakes the cabin eveyr few seconds. I'm getting idle revs ranging from 500 (!) up to 900 and everything in between. I'm seeing the vacuum reading flickering around all over the shop at idle as well, between 13 and 19 inches.

Now I'm assuming this is either something wrong with the idle speed control valve or a loose vacuum hose somewhere...I've not checked it out yet, so any ideas before I start hunting?

 

Going to have a good look around in the engine bay today.Had the same sort of thing with my Skyline it turned out to be the dump valve.Will keep you posted.
Cheers
Dan

 

Exactly the same is happening with my STI, was advised its probaly the MAF.

Have replaced today with a new one, will report back results

chris

 

Are you both using aftermarket bov's? Lucky enough i had a replacement Blitz one and exchanged it for that and also gave the idle solenoid a tweak.I'm glad to say everything fine and running sweet.Never had much faith in Blitz dump valves always been a pain.
Dan

 

Dan

I still recommend getting your maf checked out, if it has gone out of range, it is possible that the ecu has learned the revised idle settings required. The ECU can however do nothing about the power zones where it may be running lean. By running lean I mean lean enough to overheat a piston to the point it partially siezes in the bore and runs a big end bearing.
Sorry if this sounds scaremongering but the short period of idle roughness is the only hint you will get that the maf is on its way out.
I'd look on it as an opportunity to get someone to check it out cheaply before you end up with a big bill !

Andy

 

Hi Dan

Running standard bov, driving home today new maf has,nt sorted it, i've also replaced the tps.
Spoke to subaru cheam they reckon it could be o2 sensor.

The idle solenoid is that the same as the throttle position sensor?

Cheers
Chris

 

MAF sensor and/or lambda sensor, but probably MAF. Needs to be sorted ASAP.

Paul

 

Well just had a quick check over the engine bay - all the vacuum hoses seem tight, checked the boost solenoid while I was there and it's clean as a whistle so there's probably not a lot of oil knocking around the intake side, took off the hose to the idle control valve and sprayed some carb cleaner down the pipe. At least I think it was the idle control valve - there was the big hose running across the top of the engine to the n/s rear runner on the inlet manifold, with a 3-pin plug. With the hose unplugged, engine dies after a few seconds.

It might be my imagination but after squirting a bit of carb cleaner into that valve the idle seems a little more stable, but the engine's still rocking around on its mounts and shaking the car, feels like an idle misfire. Pulled the HT leads off the coil and there's a spark on each one. Each one makes the engine run worse when it's disconnected.

Anything else? From previous cars I've tried to fix, I'd suspect a dodgy lambda or coolant temp sensor to cause similar problems - is there any way I can test them out myself? Don't know whether the reference to MAF problems is aimed at me or not - but if it is, again, what can I do to test it? e.g. is there a certain resistance it should show on its electrical connections?

 

Just done a diagnostic which came up with nothing, then a read memory which showed codes 13 and 23 - camshaft position sensor and MAF sensor. Bummer. I unplugged them and gave the contacts a clean but it doesn't seem to have settled the idle. So I guess I better take it easy until I get these sorted out.

ANyone know the cost of either of these parts from Subaru?