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Discussion Starter · #1 ·
Hey guys,

Curious if anyone else has experienced this. It has been unusually hot here in North Carolina the past month with temperatures over 100 for weeks straight. I've noticed that when it is above 95 degrees and I have the A/C on...the car's RPMs will drop about 100rpms after stopping for about 15-20 seconds causing the vehicle to sputter like it is going to stall. It also causes the car to jerk forward and feels like someone has rear-ended me. The car catches itself and readjusts the RPM's almost instantaneously to prevent the stall, but its very annoying. It happens pretty much at every stoplight.

I called the service adviser who stated he would ask his techs if anyone else has reported this issue. So far, no call back. This has happened 4 to 5 times now on separate driving occasions. It goes in for it's 6k service soon, so I'm going to have them check it out then.

Any ideas? I have the 2.5 base model.
 

Master Caster
馃枻馃挃馃挋 3 Beautiful OBXTs
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16,263 Posts
I am assuming it's a Gen5? My '06 XT, the rpms actually bump up...between 50 and 75-ish. And that is from logged data. The ECU bumps the rpm to compensate for the added load. There is a tiny blip down due to the voltage draw (minor, 5-10 rpm), and then it raises.

I had a low idle issue I was chasing...so I was looking at logs all the time. Then I noticed that in the summer I had less of an issue, because the A/C was always on, so my rpms were always consistently higher at idle.
 

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2016 Outback Premium 2.5 CVT w/EyeSight+SRVD
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7,666 Posts
Any ideas? I have the 2.5 base model.
I have not experienced anything like that in my 2015 Legacy Premium. I don't know whether or not the difference in the HVAC system between base trim and Premium/Limited trims might be a factor. Regardless, what you describe is not normal behavior. The good news is that it's highly reproducible, so at least the dealer techs will be able to observe it for themselves.
 

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2021 Outback Touring, 2015 Outback (sold), 2019 Toyota LC 200, 1998 Toyota LC 100, 1987 Toyota FJ60
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768 Posts
This happens all the time with my 2015 Outback. Normally idles at 600-750 RPM but when the A/C cycles it drops for a second to 400 RPM. Most of my other cars with small engines and pulley driven AC units did that too. Nothing to worry about.
 

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Fresh Out of Outbacks!
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14,495 Posts
That sounds like a sticking torque converter. Not unlocking fast enough, so it tries to drag you forward and/or stall. It can feel like the surge on an old style ac compressor.

The 2015 has the new style clutchless ac system, so you definitely aren't feeling a compressor start.

Subaru has had trouble with some torque converters not releasing cleanly, and I felt my own hang up once.
 

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2015 Outback 2.5i (base)
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59 Posts
North Carolina here as well with a base model 2.5i. I've not experienced what you're describing in our vehicle. If you removed the phrase "... and feels like someone has rear-ended me" I'd guess that you're sensing the A/C compressor clutch engaging.

If you have your foot on the brake and it still feels like someone has rear-ended you I'd have your dealer inspect things just to make sure it's not a big deal.
 

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I too hav noticed the sputtering feel when i come to stop but never has the vehicle felt like it was jerking forward but it's only when ac is running


Sent from my iPhone using Tapatalk
 

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2016 Outback 2.5i Premium PZEV w/Eyesight in Ice Silver
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368 Posts
nhtsa complaints

http://www-odi.nhtsa.dot.gov/owners...a.make=SUBARU&searchCriteria.prod_ids=1977280

Interspersed among the windshield complaints are these:

SUMMARY:
THE VEHICLE IS EQUIPPED WITH THE 3.6R ENGINE AND A CONTINUOUSLY VARIABLE TRANSMISSION. WHEN DESCENDING A LONG HILL IN A FIXED GEAR RATIO (USUALLY 2ND OR 3RD) THE VEHICLE SLOWS NORMALLY UNTIL THE RPM REACHES APPROXIMATELY 1200 RPM AT WHICH POINT THE VEHICLE SUDDENLY BEGINS ACCELERATING UNTIL THE RPM REACHES APPROXIMATELY 2500 RPM AT WHICH POINT THE PROCESS REPEATS. I OBSERVE THE "MPG" SUDDENLY DROP AT THE SAME TIME TO AROUND 25 MPG WHEN THE VEHICLE ACCELERATES. IT RISES BACK TO "99" WHEN IT SLOWS. NOTE THAT DURING THE ENTIRE SEQUENCE MY FOOT IS OFF THE ACCELERATOR PEDAL AND THE THROTTLE ANGLE DISPLAY SHOWS ZERO. I FIND THIS VERY HAZARDOUS AS THE UNINTENDED ACCELERATION CAN OCCUR WHEN ENTERING OR WITHIN A TURN CREATING A CRASH RISK.


SUMMARY:
WHEN THE ENGINE IS COLD, THE IDLE SPEED IS 1600 RPM WHEN STARTED. WHEN PLACED IN REVERSE OR DRIVE IT REDUCES TO A NOMINAL 900-1000 RPM. WHEN THE VEHICLE STARTS TO MOVE IT SUDDENLY DROPS TO 600 RPM. WHEN BRAKING TO A STOP AFTER MOVING VEHICLE THE RPM SUDDENLY JUMPS TO 900-1000 RPM JUST BEFORE VEHICLE HALTS. THIS CAUSES SUDDEN UNEXPECTED ACCELERATION OF THE VEHICLE AND PRESENTS A SAFETY HAZARD. I BELIEVE THIS IS DUE TO AN ENGINE/TRANSMISSION SOFTWARE ISSUE. THIS HAS OCCURRED SINCE NEW.

SUMMARY:
THERE ARE TWO PROBLEMS. ONE HAPPENED TWICE. WHEN IN DRIVE AND FOOT ON THE BRAKE FOR A LONG TIME -ABOUT 3 OR 4 MINUTES. THE BRAKE GOES SOFT, THE ENGINE SPEEDS UP AND THE CAR TAKES OFF. IF SOMEONE OR CAR IS IN FRONT OF ME THE CRASH WHEN BE BAD. THE SECOND PROBLEM IS WHEN TURNING LEFT INTO A PARKING SPACE THE SAME THING HAPPENED ABOUT 5 TIMES. THE SERVICE DEPARTMENT HAS LOOKED FOR THE PROBLEM BUT DID NOT FIND ANYTHING. A FIELD ENGINEER HOOK UP A COMPUTER AND RODE WITH ME FOR ABOUT 2 HOURS. OF COURSE NOTING HAPPENED. ALSO THE SERVICE DEPARTMENT KEPT THE CAR OVER NIGHT AND DROVE IT WITH NO PROBLEMS. AS THEY ALL HAVE TOLD ME IF NO PROBLEM HAPPENS WHEN THEY HAVE IT THEY CAN NOT FIX IT. NOW I MAY TURN THE CAR BACK IN (A LEASE CAR) AND BE OUT MANY THOUSANDS OF DOLLARS OR DRIVE WITH FEAR AND HOPE NOTHING BAD HAPPENS.

SUMMARY:
UNINTENDED ACCELERATION. WHEN DRIVING AT LOW SPEEDS--WHAT WOULD TRADITIONALLY BE 1ST AND 2ND GEAR (THE CAR HAS A CONTINUALLY VARIABLE TRANSMISSION)--AND WHILE KEEPING CONSTANT PRESSURE ON THE GAS PEDAL, THE TRANSMISSION CHANGES THE ACCELERATION OF THE VEHICLE ON ITS OWN IN A PROCESS THAT FEELS LIKE IT CAN'T FIND THE RIGHT "GEAR", AND IT PROVIDES A "JERKING" FEELING (USUALLY ONLY A COUPLE OF "JERKS"). YET THE TRANSMISSION IS NOT JUST FINDING THE RIGHT GEAR FOR A SPECIFIC CONSTANT SPEED; AS IT SHIFTS AROUND, THE ACCELERATION CHANGES AND HAS, WITH CONSTANT PRESSURE ON THE PEDAL, ACCELERATED FASTER ON ITS OWN. I HAVE NEVER FELT LESS CONTROL OF A VEHICLE AS I HAVE WITH THIS ONE.

SUMMARY:
I WAS SLOWING PULLING INTO A PARKING SPACE AND JUST STRAIGHTENING OUT THE CAR WHEN I HEARD A STRANGE SOUND COMING FROM THE ENGINE. IMMEDIATELY AFTER THAT I HEARD A VERY LOUD ENGINE REVVING SOUND AND THEN SUDDENLY THE VEHICLE SHOT FORWARD LIKE A ROCKET, WENT OVER THE CEMENT BARRIER AND INTO THE WALL OF A BUILDING. IT SEEMED LIKE A VERY HIGH RATE OF SPEED, THOUGH THE DISTANCE WAS ONLY ABOUT 8 FEET. THE SEAT BELT DID NOT RESTRAIN ME AND MY CHEST SLAMMED INTO THE STEERING WHEEL. IT WAS DETERMINED LATER AT THE HOSPITAL THAT I HAD A CRACKED STERNUM AND SEVERAL BROKEN RIBS. I BELIEVE THERE WAS SOME SORT OF MECHANICAL, ELECTRICAL OR SOFTWARE PROBLEM THAT CAUSED THIS UNINTENDED ACCELERATION, AND THE SEAT BELT ALSO WAS DID NOT FUNCTIONING AS INTENDED.

SUMMARY:
ENGINE IDLE IS ERRATIC WHEN COLD. BACKING OUT OF THE GARAGE IN THE MORNING THE ENGINE SURGES 3-400 RPM MAKING THE CAR JERK FASTER AND SLOWER. THIS IS WITH ONLY THE BRAKE PEDAL PRESSED. I HAVE A SECOND IDENTICAL CAR THAT DOES NOT HAVE THE PROBLEM. TEMPERATURE IS IN THE 40'S. WHEN THE ENGINE SLOWS, YOU HAVE TO EASE OFF THE BRAKE, THEM IT SUDDENLY SPEEDS UP 50% AND THE CAR TAKES OFF. THE CYCLE REPEATS FOR A FEW MINUTES IN THE MORNINGS. THE PROBLEM IS VERY REPEATABLE -THE SAME THING EVERY MORNING.

SUMMARY:
.OF US AS TRAFFIC WAS CAUSING IT TO SPEED UP AND SLOW DOWN. WITH NO WARNING, OUR CAR SUDDENLY LURCHED AHEAD AS IF I HAD STEPPED HARD ON THE GAS PEDAL, THOWING US BACK IN OUR SEATS. AFTER A FEW SECONDS, IT HIT BRAKES AND THEW US FORWARD. IT DID NOT COMPLETELY STOP BUT RESUMED PREVIOUS SPEED. THIS CONTINUED TO HAPPEN EVERY COUPLE OF MINUTES. I TOOK THE FIRST EXIT THAT APPEARED, ABOUT TWO MILES AHEAD. I WAS VERY FRIGHTENED THAT WE MIGHT ....
 

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2015 2.5i Limited
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Same problem here. RPM's drop to 450-500 every time I come to a stop along with the car wanting to move foward. This has only started recently even though I tend to have AC on in the winter as well to help with de-fogging
 

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Discussion Starter · #12 ·
Thanks for all your responses. I would assume that the fan would be running in 100 degree weather pretty much all the time...no? It does feel like something is kicking on and the rpms are dropping for a moment, but the lunging feeling is what is throwing me.
 

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2015 Carbide Gray 3.6R
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587 Posts
Thank you ncJim, it looks like there is at least one other person with the exact same issue as I have, which is the second one you posted.
 

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2016 Outback 2.5i Premium PZEV w/Eyesight in Ice Silver
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368 Posts
Thank you ncJim, it looks like there is at least one other person with the exact same issue as I have, which is the second one you posted.
It also appears to be a pretty rare issue, but a real one, so hope the dealer can track it down for you.
 

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2006 Subaru Legacy 2.5i Limited Wagon
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I appear to have the exact same symptoms. Atlanta, GA. When AC is on and I'm in (D)rive, the car seems like it's about to stall. I've just started trying to chase this problem down. I don't have as strong as a "kick" as you do, but it does feel like the car wants to lurch forward if I let up on the brakes. I'll let you know what I find out.

I drive a 2006 Subaru Legacy Wagon Limited.
 

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Tungsten 2015 3.6R Outback
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589 Posts
On a recent road trip, I drove my 2015 3.6R OB through northern Arizona and New Mexico and into West Texas for almost 3 weeks. The temperature each day was from the high 90s to the low 100s. Needless to say, I always had the a/c at 68 degrees on AUTO. However, I did not experience the lurching or surging of the engine at stops when the a/c was on. I hope you can find the answer to your problem as it definitely needs to be fixed.
 

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I've noticed something similar with my Outback 3.6R. When I'm at a stop, and sometimes when I turn the AC on auto, I can feel the car lunge forward ever so slightly. In this situation, I have the brake pedal slightly depressed. The first time it happened, I thought the car behind me bumped my rear. Then I figured out it was activating the air conditioner that was causing this. I didn't pay attention to the rpms however.

Pretty easy to duplicate. Come to a full stop with the AC off and have the brake pedal slightly depressed. Then turn the AC on full auto. The car will lunge forward slightly.

I've since made a conscious effort to keep more pressure on the brake pedal when I turn on the AC at a complete stop. I figured this was a quirk of owning a Subaru - our first one.
 

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2011 3.6r OB Limited
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4 Posts
Hello All,

Same thing here too.

2011 3.6R Limited, 30k

A/C set to Full Auto ~70deg

Condition is hot day subie sitting in the Sun.

Start car A/C kicks to full blast with recycle on.

Car surges ( like said ) at stop lights and A/C air is kinda warm coming out.

I took it in to service a few months ago to have them look at it and no were issues found.

She did it again today, same conditions. Could it be the Full Auto setting?
 

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Discussion Starter · #19 ·
Mine is when the A/C is on more than setting #1 and it is over 90 degrees outside. I'm taking it in next week to have them look at it.
 

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Discussion Starter · #20 ·
UPDATE: My car is currently at the Subaru dealer and they are testing it out (and doing the first oil change). They said they've had several customers complain about this issue and are waiting on a reflash from Subaru. They weren't able to replicate the problem this morning (it was in the 70's) but are going to drive it again this afternoon when the temp is in the 90's.
 
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