Hi all, I just picked up an '06 STi which now has about 250mi on the odometer. I've been following the break-in instructions exactly. When idling (even after the engine is fully warmed up) there's an irregular shudder with no noticeable change in RPM or accompanying noise. Sitting in the car it almost feels like there's someone with a lot of bass in the car next to me and the shuddering is always changing with it "kicking" harder sometimes than others. I found a post about a TSB on '04's with a rough idle, but I'm guessing this isn't the problem.

Maybe I'm just being paranoid and overly conscientious about a new car and its quirks, but it would put me at ease to hear this is normal, and nothing to worry about. Thanks

 

This could be one of a couple of things - First and most likely your not used to the character of your car. The STi is a relatively raw car compared to most. Lots of road noise, the hood vibrates at speed, the trunk vibrates at speed, the gearbox is a brick sh*thouse and makes noise, you have turbo whine etc... You may be used to different noises in different cars.

It also could be something that is a issue. If you haven't moded at all, bring it back to the dealer and ask them. They have driven a bunch of STis and know what they are supposed to sound like (and what they aren't). If there is an issue, they should take care of it on warranty. New, unmoded cars are great because they aren't your problem - they are Subaru's problem. Hold them accountable for your cars behavior, you paid allot for that warranty.

 

Any mods?

 

hey thedv8, i have an '06 STI too, i've got about 670 miles on my car now, but sometimes i notice this "rough" idle as well. I think it's simply just the engine mounts (they're liquid filled) not absorbing the vibration from the engine at moments. As long as your rpm isn't fluctuating it should be fine in my opinion.

 

Thanks for the suggestions everyone. The "issue" isn't so much a sound as it is a seemingly arbitrary shudder that changes in intensity. It's a similar feeling to what my Mini would do just before the CEL would come on. While there's no CEL problem I've got some baggage from my last car and it makes me nervous. While I was at a stop light for a while today I watched the tach and the engine did intermittently go from 500 rpm at idle to about 600-700 for no apparent reason but this didn't seem to coincide with the shudder. The car has not been modded yet.

I've heard bad things about the dealer here (Steven's Creek), so I was hoping to have some idea of what the problem is before I bring it in.

 

subaru boxers have a bit of a rough idle. i thought it was an issue when i first picked up my 05 wrx and got to hear that others had the same "issue." you'll get used to it. the small shift in rpm's at idle is normal too.

 

I would not be worried at all about a +/- 200 rpm swing at idle. Is this a brand new car? You may have answered this already. If its not, check to see that someone didn't upgrade the fuel system, larger injectors will make it more difficult to hold constant idle.

 

I picked up my '06 from Steven's Creek back in September. I was used to the smooth-idling Honda/Acura engines, so the boxer engine definitely felt more like a rumble, especially at stop lights. And when you accelerate, the boxer engine definitely makes a different noise than Hondas and Acuras.

My guess is it's just the boxer engine that you're not used to. But if you are paranoid or just want to get it checked out, take it to the Subaru dealerships in Santa Cruz or Redwood City. They're both supposed to be light years better than Steven's Creek (reputed to be THE worst dealer in the Bay Area...luckily I haven't had any issues with my car).

 

I have the same problem with my 05. I took it to dealer, but they found nothing wrong. They told me there were a few other complains, and they have reported to Subaru US. Isn't the Boxser engine supposes to be smoother than normal V or inline engine?

 

Thanks for the replies everyone. It sounds like I'm just being overly paranoid.

 

Its still a brand new sooby! The computer in your car is still learning your driving habits. I just got my car back from the body shop after a crash. I had to reset my computer cuz i was getting check engine lights (DP). After i reset it i had really rough idle for like a week. Then one night i got on it on the freeway and took some corners kinda fast..........the next day i instantly noticed a difference. I think the computer just has to learn your driving habits. It should go away sooner than later. But if it persists take it to the dealer!

 

it's the boxer engine.

 

Yeah Man, It's Completely Normal. I'm Good Friends To The "sti Technician" Down At The Dealership. Before I Took The Car Off The Lot, He Explained Everything... Well Just About Everything I Needed To Know About The 06 Sti, And That Was One Of Them. So Don't Worry About It Bud...

 

Try different brands of fuel my car an 05 used to have rough idle with Shell but now runs alot smoother with Mobil. Hope it helps

 

Hey, I have a 2006 WRX. Same thing was happening to me. I took it back to the dealership and it showed up that i was running on three cylinders apparently one of the Ignition Coils went bad. I suggest returning it to the Dealer and have them inspected.