Unsteady idling? Vid attached

[NRV155]

Im sort of over trying to fix mine at the moment. So far, leaving the air con on and stopping in neutral is preventing my problem.

[Mav954]

It's tough man it's the perfect car for us practicality wise, reasonable performance, comfortable, looks good, tows the bike trailer well, just wish that bloody thing would run well! What's yours doing??

[NRV155]

Read the P0638 thread.

[Mav954]

Shit man looks like your having even more fun than me! Mine actually did the whole, cruise light flashing idle fast and erratic about a fortnight ago, idling around a car park

[Mav954]

Cleaned the MAF sensor just then and went for a 15 min drive, still no better, should I reset the ECU after cleaning it?? So now we've tried new plugs, new coils, upper engine clean, new O2 sensors, MAF clean. Guess that leaves injectors? Going to have them cleaned next service in 2000km see if that helps. has anyone got any other tips I can try?

[Dropz]

Did you change the spark plug leads?

Did you replace the air fuel sensor and the O2 sensor or just one of them?

Whenever you change anything an ecu reset can only help. With the upper engine clean did you remove the tmic and clean out the throttle body and throttle plate with cleaner and a cloth?

Has it been plugged into a scan tool an actually had all the data checked both on a road test, and stationary idling?

Has the fuel filter ever been changed?

[Mav954]

Hey dropz thanks for the ideas,

I don't believe the spark plug leads were changed, plugs, coil packs and upper engine clean was done by a local workshop, they also checked codes and said its only shown a low voltage code and to get my alternator checked. I replaced both top and bottom sensors, top one was genuine bottom one NTK, I reset the ecu then, but not today when I cleaned the MAF sensor. I'm honestly not sure when the fuel filter was last changed, grab another one during the week!

[DownUnder]

Apparently someone fixed it by correcting a loose pin on a connector. Idk but it seems like everyone having this problem (there's quite a few of us now) has had a low voltage code at one point. In my mind I'm thinking it's some sort of electrical problem. Either internally or the connectors for the pedal position sensor or the TPS(which is basically the throttle module in drive by wire)... Subaru has a few values that can by checked but you need the subaru diagnostic manual... Also the other thing that seemed to make it better for me was idling it in the driving for 10-20 minutes everyday (I find that the second I touch the throttle it almost stall but pre that it idles fine...) My idle is still a bit dicky but never goes near a stall. Idk if it'll work for you but I hope it does...

seeing as I have a 2.5i and you have a 2.0T and some other have a 2.5T I can't see it being a direct ECU problem as we have different ECU's it's gotta be some subaru part that is used across all models and has started to die after all this time.... I've seen it on the legacy forums too...

[Mav954]

It's nowhere near as bad now as it was in that original video, and doesn't really affect the driving of the car, I just bloody hate that something is wrong with it haha, but your right the more you look around te more common it is, getting Injectors cleaned next service, different things seem to fix different cars but they are all a similar problem!

[Dropz]

If its a loose pin for other people there will be a momentary lapse in voltage somewhere. Goto a subaru dealer and ask them to drive the car and check current data looking for anything out of the ordinary. Even record data and send it to subaru if the fault occurs.

I'd be hesitant to say the upper engine cleaner would have done anything. They probably just did it into a vac line which won't clean the throttle body, which is what causes a rough idle. I'd get them to specifically remove the tmic an clean the throttle body with a cloth and cleaner. Or it is a pretty easy DIY. Maybe a forum member near you would be willing to assist?

[Dropz]

Seeing as this is actually arousing my interests I'm more than happy to lend a hand if you're in Adelaide?

[DownUnder]

I'm in Adelaide. I need to get a throttle body gasket before I can rip off the throttle. If you have something that can properly log a subaru I'd be very interested

[Dropz]

Just to add more tunnels to your confusion, has anybody checked timing advance/ OSV operation? They can get sticky (common fault in gen 4 gts) and very very rarely won't log a code.


DownUnder I'm more than happy to man, might even have a gasket! Ill check tomorrow night. My scan tools not all the subaru one is, but beats nothing!

[Mav954]

Ive cleaned a few throttle bodies before, never on a boxer and never with fly by wire, cant imagine it'd be too different though might give it a go on the weekend!

[Dropz]

Other things to consider is neutral switch(this is what mine is)