Rough Idle (HOW DO YOU FIX IT)??

I know there are A LOT of forum topics on this. My car is suffering from this as well and pisses me off ! I want it fixed! Did anyone figure out how to fix this COMPLETELY? My car has almost 80k on and is an 07. No lights on dash. Everything is fine with it just rough idle when coming to a stop and when stopped. Also idles rough in reverse once in a while. Seems to go away when engine heats up completely. Can someone please tell me how to fix this?!? I want to get it taken care of right now while I have money.

 

Thanks,

Brian.

Great question!

 

No easy answer. For a while I gave up. Now I'm back at this stupid problem. It's pathetic Subaru has this problem.

 

I have a 'lumpy' idle in D and R. Cabin shake with A/C on.

Only does it when cold?

if it only happens when the engine is cold, it might be the o-rings between the intake manifold and tgv housings. that, spark plugs, and vac leaks are probably the easiest contributors of rough idle to fix.

 

some of the much more difficult to fix contributors are too-tight valve clearances, broken ring lands, etc.

if it only happens when the engine is cold, it might be the o-rings between the intake manifold and tgv housings. that, spark plugs, and vac leaks are probably the easiest contributors of rough idle to fix.

 

some of the much more difficult to fix contributors are too-tight valve clearances, broken ring lands, etc.

 

This is where I'm at. I've run through all the 'cheap and easy' fixes and still have this problem.

 

Today I'm getting a compression test, engine mount and axle inspection done up on the rack.

in the words of max capacity "Clean your MAF with a can of $7 MAF cleaner"

 

 

Oil good, coolant good? radiator cap not leaking?

I just got done cleaning the MAF, replacing the OCVs, replacing and cleaning PCV system, mine hasnt stalled yet and idle is smooth as butter, until I put AC on, but thats expected. Still waiting for it to completely learn itself. But Id have to guess OCVs were problem they were nasty

I just got done cleaning the MAF, replacing the OCVs, replacing and cleaning PCV system, mine hasnt stalled yet and idle is smooth as butter, until I put AC on, but thats expected. Still waiting for it to completely learn itself. But Id have to guess OCVs were problem they were nasty

 

What did they look like? The one I pulled was very clean looking, no gunk.

I wouldnt say they were serioulsy "gunked" up, there was slight buildup between the spring coils in the bottom of the OCV, just everything had that burnt oil type color to it. I bought new ones planning on replacing them so didnt really pay attention to what they looked like.

I wouldnt say they were serioulsy "gunked" up, there was slight buildup between the spring coils in the bottom of the OCV, just everything had that burnt oil type color to it. I bought new ones planning on replacing them so didnt really pay attention to what they looked like.

 

I pulled my driver side one out and cleaned with parts cleaner, there wasn't anything in there the wasn't just liquid oil.

 

Didn't pull the passenger side, maybe it's hotter and needs cleaning.

 

I've never had a car before that's had such well documented idle problems online without a good solution to it.

 

The gaskets did nothing for me.

Yea they didnt do anything for me either, it was good to tighten all the fuel lines and stuff while I was in there. At this point Im assuming it was the OCVs or buildup in the PCV system, but tough to pinpoint since car was down for like a month and got a rebuilt turbo and some other stuff at same time.

It pretty warm out today so I put my AC on, 65 full blast. Its blew cold like it should but the idle was terrible! I came to a stop sign my wheel locked up and the lights on the dash went on wtf! I had to shut my engine off and start it again. Put my ac on again a few blocks down did the same thing...

My buddies 05 lgt had a rough idle and it ended up being his valve clearances and he only has 86xxx miles. A couple were really tight so pulled the motor put correct buckets in and ran like melted butter. Mine idles pretty rough also and I have 135xxx miles so when I get done building my ej257 block I'm going to check the clearances but could also be a vac leak. I need to check my OCV's now lol

It pretty warm out today so I put my AC on, 65 full blast. Its blew cold like it should but the idle was terrible! I came to a stop sign my wheel locked up and the lights on the dash went on wtf! I had to shut my engine off and start it again. Put my ac on again a few blocks down did the same thing...

this is exactly what mine did, I would end up throwing it into N before it stalled, it would catch and save itself, it would normally only happen at slow speeds (traffic or parking) and had no other issues, no codes, no vac leak, I also cleaned throttle body passages for idle valve, not sure what exactly fixed mine, but I would put money on OCVs

It pretty warm out today so I put my AC on, 65 full blast. Its blew cold like it should but the idle was terrible! I came to a stop sign my wheel locked up and the lights on the dash went on wtf! I had to shut my engine off and start it again. Put my ac on again a few blocks down did the same thing...

 

I have low compression and am in the process of a motor rebuild

Anyone try contacting their Subaru dealership? I'm interested in seeing what they have to say.

Anyone try contacting their Subaru dealership? I'm interested in seeing what they have to say.

 

They act like they've never seen this problem before...

I dumped a can of seafoam in the tank and I had the same problem and haven't had the rough idle since. I might have just gotten lucky tho

Well I found out it only idles weird when I put the AC and heat on.. So I'm not gonna use it simple as that. But should I be concerned in the long run? Is it okay, or should I take it in and spend a lot of $$. It runs PERFECT without the AC and heat going! I don't get it...

Anyone try this? I was told to by a LGT owner I cruiz with. He was having the same problems as us! "I did a while ago. took off my top mount, vacuum hose was slightly off. Zip tied The connections and it has been good ever since" I'm going to try this, this weeked if I have time. Anyone know a thread that would help me take off the top mount?

Removing the TMIC is super easy, I did it last weekend. A quick search turns up this thread: http://legacygt.com/forums/showthread.php/perrin-tmic-install-walkthrough-pics-97247.html

 

I just changed my OCVs and Plugs. These either have 154K on them, or 121K (bought the car with 33K, not sure if these were changed before I bought it). Pics...

 

http://i.imgur.com/tgFWotn.jpg

 

http://i.imgur.com/DgHKwpo.jpg

 

My car had a rough idle for quite a while. Turbo blew recently so I'm hoping the new OCVs and Plugs fix that...

EDIT: The OCVs weren't too dirty in my opinion, so I doubt those were the cause...

Yeap, OCVs were my issue. Funny actually it was the left one first then the right one about 4 weeks later.

In fact I have had a spate of issue with the Lib over the last few years. First the O2 sensor by the turbo went, then both OCV’s 4 weeks apart, dirty MAF sensor in there to for good measure, one of the clips that hold the injectors on went and so that meant that the injector was not always firing and recently the RH Cam Sensor went. So nothing serious or expensive but annoying none the less. So probably took the car out of commission for several days at a time and this last one has taken the car out for several weeks (mind you I did have a OS holiday in there so not sure all that time counts). All good now though, fingers crossed, but defiantly a temperamental lady sometimes.