HELP! Engine running rough at specific RPM
#1
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Join Date: Aug 2007
Location: My Subaru
Posts: 154
Car Info: 2007 Impreza 2.5i
HELP! Engine running rough at specific RPM
Here's one for those who know more about cars than I do...
My car is a '07 Impreza 2.5i. It is stock, which obviously means no turbo, and has a manual transmission. The car has about 60,000 miles on it and I just had the 60,000 mile service performed on it. I'm having a new problem with it, as the engine has a rough spot right around 2,750 rpm which translates to 65mph in 5th gear, the posted speed limit for a lot of the driving that I do. I know it's not a tire out of balance because I can recreate the problem at any speed by getting the engine up to about 3,000 rpm and letting it decelerate slowly down to 2,500 rpm. You can also hear it while under throttle, but its not as pronounced. The crazy thing is, if you rev it past that 2,750... it sounds smooth as the day it was new. The check engine light is NOT on.
WTF is up with my car? It goes back to the shop on Friday, but I'm not very optimistic to say the least.
Hopefully my 80k extended warranty will cover whatever is going on.
My car is a '07 Impreza 2.5i. It is stock, which obviously means no turbo, and has a manual transmission. The car has about 60,000 miles on it and I just had the 60,000 mile service performed on it. I'm having a new problem with it, as the engine has a rough spot right around 2,750 rpm which translates to 65mph in 5th gear, the posted speed limit for a lot of the driving that I do. I know it's not a tire out of balance because I can recreate the problem at any speed by getting the engine up to about 3,000 rpm and letting it decelerate slowly down to 2,500 rpm. You can also hear it while under throttle, but its not as pronounced. The crazy thing is, if you rev it past that 2,750... it sounds smooth as the day it was new. The check engine light is NOT on.
WTF is up with my car? It goes back to the shop on Friday, but I'm not very optimistic to say the least.
Hopefully my 80k extended warranty will cover whatever is going on.
Last edited by shawnpdillon; 11-18-2009 at 06:49 AM.
#5
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Join Date: Aug 2008
Location: Livermore
Posts: 2,127
Car Info: LUMPY CGM 05 WRX
HHHRM I dont feel this is going to be somthing bug like a ringland or motor. Are your coil packs on tight? You said they did do a service on the motor. Did they replace the plugs? either that or vaccum leak.
#6
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Join Date: Jan 2010
Location: San Jose, CA
Posts: 85
Car Info: 1991 Mitsubishi Galant VR-4
If you have access to a Subaru Select program and or a obd2 scanner that can read airflow, timing, Knock, load, o2 sensors outputs, rpm, etc and you can recreate the problem then it should be fixable. Its under warranty so tell them that you can recreate the problem and they should be able to log what is going on through obd2 system.
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