Subaru Crosstrek and XV Forums banner
21 - 40 of 47 Posts

·
Registered
Joined
·
13 Posts
Discussion Starter · #21 ·
Have you cleaned your MAF sensor?
They told me there were no codes so "there's nothing wrong with a sensor" i know lot about cars, enough to the point that my alternator died in traffic and I was so sure that's what it was that I walked to a local store, bought an alternator and a battery (because I was sure it fried mine) and called a close mechanic to see if he could take me. However, sensors are definitely out of my scope lol. Too many electrical parts. But it doesn't feel like a spark plug. I feel as though something is clogged. Sensor or something
This seems to be a common occurence with the FB20D. Easier to see with the MT, since we can just WOT the car, and force it to operate in a fixed gear across the entire power band, seeing how the behaviour changes in the 2k-3k range. Same thing is being reported on a 5th gen impreza forum, and noone has been able to pinpoint the problem. Logs seem to indicate a pullback in timing in that RPM range, and the phenomenon tends - allegedly - to be amplified by heatsoak. Mitigation with a higher octane has worked for a few, didn't for others.

I always feel a slight bucking in that range. Easiest to notice it is under WOT in 2nd or 3rd gear, starting at 1000 rpm and flooring it. Just a few days ago (after a 3h trip, engine off, engine on 10 mins later) it was amplified to the point that the car bucked a few times.

Until someone obsessively logs the timing advance and A/F ratio over a few runs, it'll be hard to pinpoint the exact reason.
Yeah it's pretty bad bucking. My own personal mechanic was like "something is wrong that is absolutely not normal." he could feel the jerking as well. It's more than just a little jump, it's pretty severe where passengers are like swaying back and fourth lol
 

·
Registered
Joined
·
13 Posts
Discussion Starter · #22 ·
My 2018 has similar miles on it. No problems at all like you describe. The dealer is just avoiding fixing your problem. You should try a different dealer or escalate it up their management chain.

Fuel, air, spark. One of those is messed up. The obvious fixes involve replacing some parts, such as ignition coils, PCV valve, and fuel filter. My guess would be it is an ignition issue. It doesn't sound like a fuel filter because that would likely cause issues at higher rpm and power demands. PCV idk enough about that but it is simple enough to replace yourself (and relatively cheap). MAF sensor? Easy enough to clean anyhow.

Make sure there are no air leaks in the intake after the MAF sensor, which would cause mixture problems. I had a weird lean mixture problem on my motorcycle which turned out to be a split vacuum line. It was difficult to find, being in a hidden spot. Check all the hoses carefully.

Fuel injectors? Again, I am old school so this is not my forte, but while it seems unlikely perhaps you have a bad/clogged injector.

Then there is a multitude of sensors. I think this is unlikely without a code being thrown, and finding it probably requires sophisticated factory tools.

There are some pretty good OBD units which will tell you a lot of what is going on even if no code is showing. And, while unlikely, it is possible your check engine light is burned out and there is a code posted.

Good luck. What you report is most definitely not normal nor acceptable.
I was reading a other forum and some people said they replaced their knock sensors and it took care of the problem. I'm wondering if I should start there. My gas mileage has kind of tanked since this all started. I was getting 30mpg and now I get 26 which I know is normal but I was getting better gas mileage a month ago
 

·
Super Moderator
2020 Crosstrek Premium
Joined
·
1,204 Posts
They told me there were no codes so "there's nothing wrong with a sensor" i know lot about cars, enough to the point that my alternator died in traffic and I was so sure that's what it was that I walked to a local store, bought an alternator and a battery (because I was sure it fried mine) and called a close mechanic to see if he could take me. However, sensors are definitely out of my scope lol. Too many electrical parts. But it doesn't feel like a spark plug. I feel as though something is clogged. Sensor or something


Yeah it's pretty bad bucking. My own personal mechanic was like "something is wrong that is absolutely not normal." he could feel the jerking as well. It's more than just a little jump, it's pretty severe where passengers are like swaying back and fourth lol
Yeah that sounds like an ignition issue to me - what it's caused by I'm not so sure. With the horizontal cylinders, it can feel like pretty pronounced side to side jostling if they're not all firing right.
That's the rev range that I always had the most knock in my old car. I wonder if the stock tune is on the ragged edge of knock to try to achieve efficiency and power.
 

·
Registered
Joined
·
13 Posts
Discussion Starter · #24 ·
Can you take it to another Subaru dealership/service shop? They could be more accommodating.

Also, in reference to the coils...I have had bad ignition coils in previously owned manual cars that were not bad enough to throw codes, but were definitely bad and on their way out. Usually, the car would idle rough, almost to the point of sputtering, and accelerate poorly, just like yours. There was no way to pinpoint which coil was bad without the code, so the next best thing was to either wait for the code or to one coil at a time and hope that you'd get lucky and find the bad coil. That would only work it it was indeed just 1 bad coil.

Not sure what the limits are on used cars and the 3yr/36K miles warranty, but has your car passed that mark? If not, definitely push the dealer to resolve this. You may need to get SOA involved if the dealership isn't helpful.

I agree that hesitation btwn 2K-3K rpm is definitely not normal. The person at the dealership that said it is full of crap. Most manuals will have a moderate amount of power in that range.

One question...does that lack of power in the specified rpm range occur in one specific gear or it occurs in each and every gear?
It's in every gear but 1st. 2nd-6th and feels about the same in each. It was happening kind of intermittently so it was hard to pinpoint before, but now it does it 98% of the time during pretty normal acceleration, I don't even have to really step on it anymore for it to bog down and stumble/jerk. I fortunately it is out of the 3 year warrenty. The previous owner bought it 9/2017. It's almost 4 years old. Actually now that you mention it, I think it was a lease. She traded it in 9/2020. I bought it in April so the car sat on the lot from 9/2020 until 4/2021. I don't know if that man's anything
 

·
Registered
2021 Subaru Crosstrek Limited
Joined
·
457 Posts
Given your last post and other things you have said, it all seems to point to injectors, coils, etc. You mention the vehicle might have been leased before you bought it.

Did you buy this from a dealer?
 

·
Registered
Joined
·
13 Posts
Discussion Starter · #26 ·
Given your last post and other things you have said, it all seems to point to injectors, coils, etc. You mention the vehicle might have been leased before you bought it.

Did you buy this from a dealer?
I bought it from a handy gmc dealership so they have 0 idea what to do for me. Subaru never had a good deal on crosstreks. I waited for this one and the price dropped so I snagged it. I have taken it to subaru as well and they also are at a loss. They just said "yeah that happens with the 6 speeds. You just have to cruise at 3k rpms" I looked in the manual and it didn't say that lol. All the shift ranges are in there.
 

·
Registered
Joined
·
62 Posts
It's in every gear but 1st. 2nd-6th and feels about the same in each. It was happening kind of intermittently so it was hard to pinpoint before, but now it does it 98% of the time during pretty normal acceleration, I don't even have to really step on it anymore for it to bog down and stumble/jerk. I fortunately it is out of the 3 year warrenty. The previous owner bought it 9/2017. It's almost 4 years old. Actually now that you mention it, I think it was a lease. She traded it in 9/2020. I bought it in April so the car sat on the lot from 9/2020 until 4/2021. I don't know if that man's anything
Where are you located? There may be be some sort of lemon law that covers this.



Hopefully, you're located in one of the six states that have used car lemon laws.
This shouldn't be something that is brand sensitive. It's something mechanical so the gmc dealership should at least make an attempt to troubleshoot it.
You could take a more stern approach with the gmc dealership and see if they'll help.
Another thought would be to contact SOA and see if they can help . Maybe they can put you in touch with a dealer/service dept that can be more helpful.

I reiterate that the dealer that told you "it happens with 6 speeds" is full of it.

Definitely try another Subaru service dept, otherwise, you may have to find a trustyworthy mechanic that will not overcharge to troubleshoot and resolve the problem. Problem with the 2nd option is that it could become costly because of all the trial and error associated with parts and labor. Even if you're mechanically inclined and can do this yourself, you may end up paying for parts that don't solve the problem initially. Becomes wasted money, aside from time invested.

Hope you find a resolution soon!
 

·
Registered
Joined
·
13 Posts
Discussion Starter · #29 ·
Where are you located? There may be be some sort of lemon law that covers this.



Hopefully, you're located in one of the six states that have used car lemon laws.
This shouldn't be something that is brand sensitive. It's something mechanical so the gmc dealership should at least make an attempt to troubleshoot it.
You could take a more stern approach with the gmc dealership and see if they'll help.
Another thought would be to contact SOA and see if they can help . Maybe they can put you in touch with a dealer/service dept that can be more helpful.

I reiterate that the dealer that told you "it happens with 6 speeds" is full of it.

Definitely try another Subaru service dept, otherwise, you may have to find a trustyworthy mechanic that will not overcharge to troubleshoot and resolve the problem. Problem with the 2nd option is that it could become costly because of all the trial and error associated with parts and labor. Even if you're mechanically inclined and can do this yourself, you may end up paying for parts that don't solve the problem initially. Becomes wasted money, aside from time invested.

Hope you find a resolution soon!
There is a lemon law in VT where I am but you apparently have to first try and unsuccessfully have it serviced "within the factory warranty" which is stupid because I just bought it and it was out of warranty when I bought it. But it's ok. I'll assess the recall situation again and see what they say. And bring up this forum and expain that I'm not the only one who has this issue, and that my own mechanic said it was not right at all. I do intend to call SOA and open a claim with them as well. That's a great idea and never thought of that! I thought calling themwas only if you had a major issue and wanted to report a dealership lol. I've had issues with a local Subaru dealer in the past and switched to one out of state. (the one in my state replaced a brake sensor wrong in my old car and my brakes locked up in 6 lanes of traffic and they told me to drive it back to them. It screwed up my brakes and fried my clutch a bit, then I asked them to check a filter and they said it was fine and I checked it myself and found a rat and nest in it the next day. Needless to say I ripped them a new a**hole and will not be back). So I guess I'm having a hard time finding a good Subaru dealership that will address my issues seriously. Everyone thinks I'm a young female and have 0 idea what I'm talking about. But I grew up with a cert intelligent mechanic and had a sh*t Honda civic that needed literally everything replaced. So I know quite a bit about cars from spending time with my mechanic. So sad he's leaving. I don't know what I will do for service now
 

·
Registered
2021 Subaru Crosstrek Limited
Joined
·
457 Posts
Man, that sucks. A car manufacturer is represented by the dealer, whether they like it or not. You would think it would be in their best interest to get the shady, slimy dealers out of their network.
 

·
Registered
Joined
·
96 Posts
There is a lemon law in VT where I am but you apparently have to first try and unsuccessfully...
It appears that there is a recall for this issue and the recall was reported on April 15th but went to effect on May28th, I was going to suggest that this is an ECM problem and was looking for ECM pricing for you and I found this:

Here is the NHTSA recalls list for your vehicle. Look at "ECM Software may cause stall"

Here were my thoughts before I found the article:

The way it sounds to me is not a coil, spark plug or injector issue because you would definitely have that same issue on 1st gear at some point. It is also unlikely that it is a sensor since you do not get any codes. It sounds like an engine mapping issue. They may need to hook it up and update the ECM software.
 

·
Registered
2021 Crosstek 6 sped manual
Joined
·
1 Posts
I have this same issue on my ‘21 Crosstek.

For mine, the problem gets worse when the fuel is 1/3 of a tank or less.
 

·
Registered
Joined
·
767 Posts
I have this same issue on my ‘21 Crosstek.

For mine, the problem gets worse when the fuel is 1/3 of a tank or less.
This could be caused by water in the fuel.When you fill the tank,the water is diluted and it runs good.The closer you get to the bottom of the tank,the higher the concentration of the water and the worse it runs.Try running some dry gas in your fuel for a tank or two and see how it does.
 

·
Registered
Joined
·
13 Posts
Discussion Starter · #36 ·
This could be caused by water in the fuel.When you fill the tank,the water is diluted and it runs good.The closer you get to the bottom of the tank,the higher the concentration of the water and the worse it runs.Try running some dry gas in your fuel for a tank or two and see how it does.
I haven't been driving as much (I used to drive about 60+ miles a day for work, now I'm just driving around town, got a new job 5 minutes from my house) and I haven't noticed the problem nearly as much! Temp has ranged from 55-95 the last couple weeks. It's a little jumpy occasionally but the bogging down and stuff I haven't noticed. Will have to take it on a long drive sometime and see what that's like. I'm excited right now, hoping it won't do it again!
 

·
Registered
2021 Crosstrek Base 6MT PYP
Joined
·
38 Posts
I remember reading this forum before I got my 2021 6MT and saw some speculation about faulty knock sensors and the ECU learning the false knocks and adjusting the timing for the RPM range. It would be interesting to see signal with an oscilloscope. Might be able to filter these false signals with a capacitor, RC, LC or LCR circuit. But we would need to replicate a real knock signal to make sure we don't filter the data that the ECU actually needs. Anyone know how to clear the ECU so that it will learn again?
 

·
Registered
Joined
·
10 Posts
My 2019 Crosstrek 6 speed manual has the same problem. I bought it new, and the problem began at about 6000 miles. it has been intermittent. Last year one time it was so pronounced it was dangerous when I turned onto a street and downshifted to second gear. Most of the time it is just annoying. Sometimes it runs perfectly and it is very responsive between 2-3K RPM with no hesitation and pulls nicely! Last year I took it to a dealer when it was hesitating and a tech drove it with me up a steep hill. He had to downshift to first gear to make it to the top. Normally it will fly up the same hill in third with no problem. They were going to consult with Subaru, and I never heard back. I haven't identified any pattern to it, and all of the recalls have been done including new coils. The service department tells me they have not heard of this problem before. I believe that considering the small number of 6 speed Crosstrek's sold. If models with CVT's have the same problem, I imagine that it might mask the hesitation better. I'm going to try the dealer again and also contact Subaru and report the problem before 36K warranty expires and hope for the best.
 

·
Registered
Joined
·
10 Posts
I remember reading this forum before I got my 2021 6MT and saw some speculation about faulty knock sensors and the ECU learning the false knocks and adjusting the timing for the RPM range. It would be interesting to see signal with an oscilloscope. Might be able to filter these false signals with a capacitor, RC, LC or LCR circuit. But we would need to replicate a real knock signal to make sure we don't filter the data that the ECU actually needs. Anyone know how to clear the ECU so that it will learn again?
I believe my ECU was reset by the dealer when both ignition coil recalls were addressed. It still hesitated a little when I drove it home.
 

·
Registered
Joined
·
2 Posts
Adding my 2 cents to everyone else's here. I am experiencing the exact same issues. Car is a dream to drive @5 to 10% of the time. Plenty of power, smooth. The rest of the time it varies between unpleasant to downright undriveable. It bucks, hesitates and limps to the point of being almost unsafe. Dealer said they have never heard of this issue and could not find anything wrong. I had hooked up my scan tool and took video of some logs while driving it. You can clearly see the timing running [email protected] degrees advance and then dropping right off to -10 to -12 right when it bucks and slows down. Mechanic watched the video after not finding anything and put in down as knock sensor a. They replaced that a week later, but it did not help at all. Told them about it and I got a we will look into it. That was days ago and nothing. Very frustrating. I like the car, especially the the 6MT. Fun to drive. No way I can take it on the interstate the way it is though. It will barely get to 55 a lot of the time floored in 5th gear.

Plan to do more logging to see if i can capture any relevant data. Hopefully someone will figure it out for all of us at some point.
 
21 - 40 of 47 Posts
Top