Rough idle

[miggi747]

My Levorg 1.6 sometimes idles low (600-ish rpm) and the car shakes when I'm stopped or about to come to a stop. It feels like it's going to stall. And when the car realizes this, it gives the engine a little rev and idle goes back to normal (or I give the accelerator a little blip). I thought this happens when the engine is cold, but it also occurs when everything's up to temperature.

I plan to check/replace the air filter element and clean the MAF sensor, but I'm still not sure why the issue would exist in the first place. The car has done 80,000km. Does anyone have any insights on this? Would love any sort of tips or guidance.

 

[Robsyuk]

The maf being dirty can cause this.

 

[robo498]

Do an idle relearn. Look on you tube for "mr subaru" he has a video

 

[iggorsky]

It is worth checking MAP sensor too.

 

[miggi747]

Thanks for chiming in everyone. So far, I've given the MAF sensor a quick clean and did an idle relearn after that. The rough idling still comes up but not as much as before. I would say only when the engine is really cold.

I've been putting off messing with the MAP sensor and the throttle body because of the hassle of removing the intercooler. But I think that should be my next step.

 

[miggi747]

Thought I'd give an update here just in case anyone is experiencing the same issue. Took the car back to the dealer since it was still under warranty. They cleaned the throttle body resulting in a noticeable improvement in throttle response and initial acceleration. I haven't experienced the shaking during my drive home but I'll take the car out again after work to see if the issue is gone.

For now, it seems like the throttle body was the culprit. However, I wasn't expecting that since the car came from Japan which is a relatively clean country compared to my homeland (Philippines). I owned an Impreza there and I have seen the throttle body properly dirty.

 

[miggi747]

Hi all. Thought I'd update you on this issue. Two days after the rough idle was supposed to have been solved by cleaning the throttle body, my check engine light came on. Conveniently, it happened when I was out of town on a long weekend. Had to nurse the car for around 400km in order to get home.

Once I got back, I scanned the error codes and got a P000A and P0017. Something related to camshaft/crankshaft position sensors. My research pointed the culprit to the oil control valve (or valve timing solenoid for some). I brought it back to the dealer since I still had 24 days before the warranty expires. I did show them the error codes but I would just let them figure out what needs fixing since I could be wrong.

I heard this is a common issue with the FA/FB engines so I'm wondering if anyone had the same issue.

 

[miggi747]

Quick update. After almost a week in the shop, my Levorg is back. The dealer couldn't exactly remember the part that was replaced but so far, the rough idle hasn't come back.

Of course, I will observe the car closely as the warranty period expires within this month. As much as I want to say so far, so good, I don't want to jinx it.

 

[Robsyuk]

Can't remember what part they not got a receipt for the part they fitted. Hopefully the maf or other sensor was just dirty and needed a clean out.

 

[Nzlevorg]

Did you find what part they replaced? Handy to know as my levorg is idling rough

 

[miggi747]

My dealer couldn't remember which part they replaced. But judging from the P000A code which is now gone, odds are it might be the oil control valve.

 

[Robsyuk]

Here's the idle relearning procedure. Sometimes I find it easier to read rather than keep pausing videos.

https://forums.nasioc.com/forums/showthread.php?t=2209950