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Subaru Forester 2015 Sputtering when at low RPM

The vehicle drives fine once maintaining speed. However when I begin driving the RPMs will occasionally jump or buck up and down. Any suggestions for what I should try and replace?

The Subaru has approximately 92k miles.



Sounds like a transmission problem.
BTW, Valvoline Oil Change sure made their quota on cabin air filters.


Yup. Take it to a reputable independently owned and operated shop.
If it’s a manual tranny, the clutch may be slipping.
If it’s an automatic, it may have a failing torque converter, a failing tranny, or a failing TC lockup clutch… or any related parts.
Or, it could simply be the need for a long overdue spark plug change. If it’s still on the original plugs, they’re due.

And, why the Carfax? Is this a vehicle you’re considering buying? If so, keep looking, and don’t believe Carfax reports. They present themselves as having access to a comprehensive database, but the truth is that none exists. They simply take whatever data is volunteered to them… and I’ve personally begun to believe they make stuff up. When looking one up, they’ll say “19 items reported against this vehicle (or some similar wording). Get the full report for $XX.xx”. They only make their money if you order a full report, so they need to be sure every car has something reported against it.

I talked to Subaru of little rock. They told me since I purchased it only approximately one month ago that I need to keep driving it until the check engine light comes on. Otherwise there’s no way to know whether or not the transmission is having any issues. Does this sound correct?

It’s correct if the shop is a dealership. They specialize in remove and replace work, not much interest in diagnostic work as it takes too long and doesn’t have a flat rate charge. You need a mechanic who knows Subarus. Look in the “Mechanics Files” link at the very top of this page.

Does it idle at a steady and correct rpm? It does sound like a slipping transmission or TC, agree w/above posts, but there’s another problem sometimes reported here involving clogged fuel injectors. They work ok at full speed when they are spraying full force, but have a hard time metering out the proper amount of fuel when not much fuel is required. Especially consider this if the problem occurs in slow speed neighborhood driving, not involving a lot of accelerations, just slow speed going straight and slow speed turning. It wouldn’t cost much to run a couple bottles of fuel injector cleaner through the tank, might be worth a try to see if it makes any difference or not. I notice the fuel filter was replaced at 60K, maybe some complaint at that time about clogged injectors.