I have a 2018 Subaru Forester with the 2.5 NA engine with about 45k miles. Got it around 2020. I had a 2007 2.5 NA Impreza before this that I got up to about 130k miles so that's my reference point.

The Forester feels under-powered up to 3k RPM. Sometimes the power seems to come on right around 3K light a light switch. It's not a whole lot better above 3k but it's a definite jump.

The car also doesn't accelerate smoothly, the acceleration seems to stumble a little bit repeatedly. Reasonably certain it's not the clutch: the RPM doesn't shoot up, no burning smell. I don't hear pinging. No warning lights.

This all seems worse in warmer weather and that's without the AC on. If the AC is on, it feels even worse. I generally turn off the AC when I'm merging onto a highway.

My old Impreza had less power in hot weather, pinged like crazy, and wasn't all that powerful either but it was over a decade old with 100k. It also didn't have the weird step up in power at 3k and didn't stumble. I took the Forester to the dealer, they flashed the ECU with an update. Either it made a small improvement or the weather got colder. Based on their handling of my old Impreza, I don't have too much hope there.

Is something wrong with the engine or is this just how Subarus are tuned for fuel economy now?

  • How long have you had the foz? Any check engine light?
    – ajayel
    Apr 17, 2023 at 9:47
  • @ajayel Got it a few years ago; winter of 2020 I think. Haven't driven it a whole lot with the pandemic. No warning lights. Edited this info into the post. Apr 18, 2023 at 11:41
  • Has the Forester always felt underpowered or is this a recent development? Can the car breathe OK, ie good air filter, clean throttle body, vacuum lines all connected up, no exhaust leaks and such.
    – ajayel
    Apr 22, 2023 at 19:25
  • @ajayel I think it's getting worse. Definitely worse than it was on the test drive but that was in cold weather and it behaves better in those conditions. Unfortunately I don't have time to dig under the hood any more but I do take it to the dealer for scheduled maintenance and hopefully they would have found something obvious like a loose vacuum line. It does have that down-pipe rattle that the notice went out on last year. Apr 24, 2023 at 17:58


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