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Old 02-23-2011, 12:41 AM   #1
normc
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Default Question on New Car - engine idle/rough? - what can I expect from 2.5L new engine?

Hi I purchased a new 2011 Subarau Impreza 2011 2.5L automatic, and I'm new to the subaru's does the engine idle rough? (but they drove it 2 hours delivered to my local dealer) so it had 180 miles already -- plus whatever test drive miles were already put into it. (where it came from it snows occasionally don't know if they warmed up car..learned after)


Example this evening 52 deg .. start engine, while waiting for the little BLUE TEMP indicator to disappear the engine idled really rough, shakes-some point sounds as though engine starts to choke/die ..just slighly tho, ... then after warm up less rough, but still idles rough - my old 2000 jetta VR6 idles rough but after warm up sounds more smooth? This one idles just less rough.. . Could be engine design of subie I don't know?

What can I expect from a new Subaru engine?
I'm quite new to the forum and subaru's ... probably should goto another dealership test drive another car to check? But off hand just wondering.

Thanks
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Old 02-23-2011, 05:21 AM   #2
williaty
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They do tend to shake a little bit more than many other engine types. However, any uneven-ness (I guess) in the the pattern of the engine is probably not right. I mean if it constantly does the same thing without any variation but it's just a lot of vibration, you're probably good. However, if you get shake-shake-shake-pause-SHAKE-shake-shake or something like that, that's no good.
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Old 02-23-2011, 07:27 AM   #3
Uncle Scotty
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take it back to the dealer and tell them that you are having this issue

it may be as simple as bad gas
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Old 02-24-2011, 10:15 AM   #4
kero
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Hmm, I always found the 2.5 NA engines to idle smooth as a babys ass, after my uel exhaust setup, she idles rough but before that, it was hard to tell the car was even running most of the times.
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Old 02-24-2011, 11:57 AM   #5
Rudgers73
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I have noticed with my last 2 Subarus that after a highway run if you are at a light the idle will be a little rough. I actually recall reading a review about the Impreza when I was first shopping for one that mentioned rough idle.
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Old 02-24-2011, 12:24 PM   #6
bradyarz
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Quote:
Originally Posted by normc View Post
...but they drove it 2 hours delivered to my local dealer) so it had 180 miles already ...

that's some fast driving on a brand new engine.
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Old 02-24-2011, 12:54 PM   #7
Rudgers73
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Quote:
Originally Posted by bradyarz View Post
that's some fast driving on a brand new engine.
4200 RPMS for 2 hrs! poor car...
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Old 02-27-2011, 02:15 AM   #8
cbigbie191
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My last two Subaru's would idle a bit rough, but after 2k miles or so and especially after the first oil change they both smoothed out nicely.
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Old 03-01-2011, 12:17 PM   #9
connorlug
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I would either say its bad gas or maybe a faulty 02 sensor? I need a new 02 sensor and it makes the car idle rough
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Old 03-01-2011, 12:59 PM   #10
T Wrex--OH
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IMO it's most likley in your head and there is no problem at all.

Boxers idle lumpy compared to straight or v-engines. At least every boxer that I've seen idling.
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Old 03-02-2011, 02:55 AM   #11
LonelyHiker
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A 4 cylinder boxer is a balanced engine (like a straight 6) but the firing pulses are quite noticeable. 4-cyl boxers come with a somewhat heavy flywheel to offset this, but there will still be a bit of a pulsation that you might not notice with other engine types. As long as the pulses are smooth and consistent, it's probably normal. If they are rough or the engine is shaking, that might not be good. Keep an eye on it. My 2010 didn't have any roughness when new.
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Old 03-02-2011, 09:30 PM   #12
T Wrex--OH
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Quote:
Originally Posted by LonelyHiker View Post
A 4 cylinder boxer is a balanced engine (like a straight 6)
Not to nit-pick, but the H4 doesn't have the same, one piston goes up as another goes down, balance as the straight six's. Now, on the other hand, the H6 Subaru engines do.
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Old 03-02-2011, 11:27 PM   #13
renyo
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Quote:
Originally Posted by T Wrex--OH View Post
Not to nit-pick, but the H4 doesn't have the same, one piston goes up as another goes down, balance as the straight six's. Now, on the other hand, the H6 Subaru engines do.
Yes it does.

It isn't balanced in a sense it wants to vibrate around an axis going through the top of the engine...
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Old 03-03-2011, 12:20 AM   #14
T Wrex--OH
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......

Last edited by T Wrex--OH; 03-03-2011 at 12:34 AM. Reason: Not trying to start a pissing match
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Old 03-05-2011, 11:50 AM   #15
impreza25i
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Yea, it always shakes =/
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Old 03-05-2011, 10:23 PM   #16
djinn
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Does it Idle rough then smooth after warming up?
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