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Discussion Starter #1
When beginning to accelerate the engine begins to stumble, like it is not getting enough fuel, then it surges forward suddenly. Also, when the transmission is in reverse the throttle is very sensitive. Complained to Subaru service about this. They said it was normal operation. I feel it could be a safety issue. Has anyone had this same problem and was able to resolve it?
 

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Same issue on acceleration. Went for a small window between cars and it always falls on its face. I replaced the pitch stop with an aftermarket one thinking engine rocking was to blame but nope.
 

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Mine ONLY does this just after a cold start (ambient temp below 40f) Very light throttle-position causes engine surging. I am sure this is related to the cold-start programming within the computer. (fuel, timing, valves...etc)

Other folks have reported this effect becomes less as the engine breaks-in and loosens-up.
 

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I'm still waiting for it to loosen up then. Almost 30k in, and it's still an unwelcomed surprise everytime mine randomly does it. Hot, cold, fresh start, running for 2 hours... has happened in all situations.

The more I step into the throttle hoping it will recover, the more it bogs and stumbles.

Last time at the dealer when I brought it up (3rd time now), they test drove it around and could not replicate and everything is functioning as normal blah blah blah..

Note: The car also had the exact same mileage as when I dropped it off, so I'm not sure they put in the effort. When I asked the manager how much they could have tested it without changing the mileage, he said "they have a test track", got up and walked away and never came back.

SUMMARY: Subaru knows something is wrong, they don't know what to do about it so they won't acknowledge it.
Thanks for your time.
 

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I'm still waiting for it to loosen up then. Almost 30k in, and it's still an unwelcomed surprise everytime mine randomly does it. Hot, cold, fresh start, running for 2 hours... has happened in all situations.
I had a weird engine dying problem which was ultimately fixed (I think) by having engine/throttle thresholds reset by a piece of dealer hardware which had it's firmware updated.

With me, it was when the AC was active and I was cruising at low speed in the parking lot - the engine would just die unexpectedly.

The last straw for me came when it died in expressway stop-and-go traffic.
 

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That sounds similar to the first time around visit. Active grill shutter coding update or something. Seemed to be better for a while, or I tricked myself into believing it, but maybe they are seprate situations.

Leaving a shopping center today, it reversed out of the spot normal, pulled forward normal till I stopped when another car was backing up. Went to go forward again and the car fell flat on its face and acted like it didn't have a throttle. It surged, Rpms popped up and it took off in a leap.

It reminds me of a older car with a dead or worn spot on the TPS. But everything is functioning as intended they say.
 

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Leaving a shopping center today, it reversed out of the spot normal, pulled forward normal till I stopped when another car was backing up. Went to go forward again and the car fell flat on its face and acted like it didn't have a throttle. It surged, Rpms popped up and it took off in a leap.

It reminds me of a older car with a dead or worn spot on the TPS. But everything is functioning as intended they say.
Problem is (I think) that there's a constant war going on: they want to keep RPMs as low as possible to promote good fuel economy, but need to keep the vehicle drivable as well.

So, they drop RPMs to conserve gas, but the extra load of the AC makes the RPMs dive lower - below the speed required to keep the engine running, or so low that it takes a while to spin the engine up for acceleration. Since everything is controlled by computer nowadays, the lower threshold at which the engine is goosed to keep it at a usable level are critical. They're probably constantly fiddling with input parameters: (Is the AC on? How much is it contributing to diminished RPMs? Goose it a little earlier to prevent a stall state?) and when your engine is initialized at the dealership, it gets the parameters that were in vogue at that time because there are no over-the-air updates.

Anyway, best of luck. Hopefully your dealership's equipment is running at the latest firmware levels.

P.S. Not sure if every dealership updates their stuff with each firmware release; I could easily see there being an attitude of "If it ain't broke, don't fix it", which may actually be a good idea in most cases. Look at the roller coaster that is Windows maintenance.
 

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Discussion Starter #8
I'm still waiting for it to loosen up then. Almost 30k in, and it's still an unwelcomed surprise everytime mine randomly does it. Hot, cold, fresh start, running for 2 hours... has happened in all situations.

The more I step into the throttle hoping it will recover, the more it bogs and stumbles.

Last time at the dealer when I brought it up (3rd time now), they test drove it around and could not replicate and everything is functioning as normal blah blah blah..

Note: The car also had the exact same mileage as when I dropped it off, so I'm not sure they put in the effort. When I asked the manager how much they could have tested it without changing the mileage, he said "they have a test track", got up and walked away and never came back.

SUMMARY: Subaru knows something is wrong, they don't know what to do about it so they won't acknowledge it.
Thanks for your time.
I totally agree with you! Did you receive from Subaru a one year extended warrantee on the transmission? I did but they didn't explain why. Being you have the Sport model when you place the tranny in manual mode and drive using the paddle shifters you do not experience the problem at all, do you? I have the Limited model which has the dual transmission modes. When I switch to Manual Mode everything clears up.

My wife and I love the car except for this problem. I took a lease and have over a year left on the lease and would like to buy the car after the lease but I can't with this problem. I have been to the dealership twice about it and it is documented about the complaint. I've come to the conclusion that it is the tranny or the programming controlling it that is the problem. The transmission is roaming when it shouldn't be when in Auto Mode. Also, it seems to be an intermittent problem. Sometimes it works fine.

My next step is to visit the dealership again OR a different Subaru dealership where that dealership may want my business and will spend the time trying to fix it. I will also write a letter to Subaru Corporate about the issue.

Thanks for your entry on the Impreza Forum. Now I know I'm not crazy. Someone else has the same issue. If I get better results finding the answer I will let you know.

Thanks, Tomflyer
 

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I have had a similar issue since new.
When I go to take off and make a left turn I get no response for the throttle. I step on the gas and RPMs do not change. It happens once a week. Had been good for a while after Subaru reflashed the ECU. Now it's back and worse then ever
After 3 or 4 times stepping on the gas the RPMs start to go

Worst thing about it NO CELS? WTF Subaru car falls flat ion it's face and no CEL
Getting a bit frustrated with the car
 

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A couple weeks ago I visited the dealership and spoke with the service manager and the Subaru Rep. They both said the problem was I didn't drive the car enough being I only have about 6500 miles on the car. They said the computer hadn't learned my driving habits. I went over the fact the problem didn't show itself when the tranny was in Manual mode. Weather seems to affect it also. Hot humid days it is worse than in dry cooler weather. I got the feeling they are trying to explain away what they don't know. I have 15 months left on my lease. As much as my wife and I like the car I won't buy it at the end with this problem. Next step is writing a letter to Subaru Corporate and at least stating my complaint. 2017 Blue Impreza Limited Tomflyer
 

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What RPM does your car idle at when in gear with the brakes applied? Does it go up when releasing the brakes. Car should be fully warmed up when checking. Wait a couple of minutes after starting even though the car is warmed up.
 

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RPM stays steady at 750, brakes on and off, tranny in drive, fully warm. Problem is intermittant. I thought humidity had something to do with it but that's not it. Been humid all day, ran normal this morning, this afternoon very bad. It acts as if the tranny doesn't know where it is supposed to be. Put it in manual mode it runs great.

When accelerating the car remains in a lower gear until about 15 to 20 mph, then shifts to high gear and stays there, unless throttle demand dictates otherwise according to Subaru service technicians. In my case the demand for more acceleration is there but the response from the tranny to move into a lower gear is delayed for a second or two until it finds where it should be which results in the car dogging then surging forward.

Subaru doesn't seem interested in finding the problem or they don't know the answer. Other than this problem I really like the car. However I probably will never buy another Subaru! Tomflyer
 

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RPM stays steady at 750, brakes on and off, tranny in drive, fully warm. Problem is intermittant. I thought humidity had something to do with it but that's not it. Been humid all day, ran normal this morning, this afternoon very bad. It acts as if the tranny doesn't know where it is supposed to be. Put it in manual mode it runs great.

When accelerating the car remains in a lower gear until about 15 to 20 mph, then shifts to high gear and stays there, unless throttle demand dictates otherwise according to Subaru service technicians. In my case the demand for more acceleration is there but the response from the tranny to move into a lower gear is delayed for a second or two until it finds where it should be which results in the car dogging then surging forward.

Subaru doesn't seem interested in finding the problem or they don't know the answer. Other than this problem I really like the car. However I probably will never buy another Subaru! Tomflyer
Yeah, this whole thread is exactly what I had made my thread about a year ago. Seems more people are having the same issue. I took my Impreza to the dealership 8 times to try to get the problem fixed, and created two cases with Subaru Corporate over it. All of them said it was normal and that's how the car was supposed to drive. I traded it in last June, can't stand how poor the customer service was and how poor the dealerships are in my area.

Just a tip, it's not the MAF sensor, tried replacing mine at my own cost and it did not solve the issue.
 

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I have this too. Bought the car new June 2017. I've had on-going issues with oil consumption that resulted in the short block being replaced about a year ago. Everything was better for about four months, but then in April it started doing a stumble between 2,000 and 3,000 rpm, losing power as I tried to accelerate and then surging ahead above 3,000. Took it to dealer twice, both times they said they couldn't replicate issue, 2nd time it came back with a note on the bill that this issue would be solved if I just remembered to downshift because the car is a manual and it won't do it automatically for me as an auto would. I've been driving stick for 30+ years and I'm pretty aware of that. So I've just continued driving and it's getting more and more frequent and I'm about ready to submit it for a lemon law claim.
 

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This is a classic symptom of CVT automatics. If you have the paddle shifters, just downshift. Or just do it from the stick on models which don't have the paddles.
 

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I seem to have the opposite problem. I have a 2019 and it seems to constantly get stuck in a higher gear than it should be in and slower to respond with a downshift.
 

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My wife just got a 2019 CrossTrek, which I believe is basically the same car, different body.

I immediately noticed her gas milage was far superior to mine, often showing an instantaneous milage in the 30-40 mpg range. I spoke to another CrossTrek owner who says she gets 31 mpg.

Looking over my logs, I can see I haven't gotten past 17 mpg since May. My last half dozen fill-ups were 16.9, 14.9, 16.8, 14.1, 14.2, and 11.6.

I'm retired now, and don't drive much expressway (used to be 30 miles each way), but I'm beginning to think that to fix my engine dying problem they seriously detuned my engine.

Can anyone tell me what they're getting on a 2018 Impreza just puttering around neighborhood?

-- Thanks, Verne
 
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