2015 WRX "rough ride" issue

[striktlysubie]

(Reposting this to a few places, as the only previous suggestion was "go back to your tuner". Did this, had the car plugged in and drove for a solid 20 minutes, and all parameters were "perfect" with no notable issues, and of course the problem did not occur when I was there):

Car is still, on occasion, running rough (i.e. "bucking", misfiring?) when under light to moderate constant throttle at low cruising speeds. Still can't really identify any other triggers for the issue. Not throwing any CEL codes, and once I blip the throttle a bit, the issue stops. Car is basically FBO with a good tune at about 292HP. We've also monitored for cylinder noise and knock, and all figures are "normal". Attaching some recent shots of my Accessport gauges taken over the last few weeks after these drives, to maybe see if there are other ideas. I feel that the "AF Correction 1" swings are pretty large, so not sure if that indicates anything glaring. Thanks for the help crew.

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[PollyPoger1]

When was the last time u cleaned ur maf and iat sensors?

[basyager]

clean MAF MAP change spark plugs and your high performance machine is due for an o2 sensor replacement... if you do all those it will run good again.

[striktlysubie]

^ The MAF was given some cleaning TLC when the tune and some mechanical work was done back around November 2022. The IAT... not sure. The spark plugs are also fairly new, as is the front O2 sensor. But, I do have new OEM parts of both of these, so wouldn't mind getting these new ones put in.
What I can also say from also posting this issue to a popular Facebook WRX group is that I'm not the only person having this exact same issue. Modded or not, other owners have experienced this same roughness/"bucking" problem in the same power band area.

[striktlysubie]

^ The MAF was given some cleaning TLC when the tune and some mechanical work was done back around November 2022. The IAT... not sure. The spark plugs are also fairly new, as is the front O2 sensor. But, I do have new OEM parts of both of these, so wouldn't mind getting these new ones put in.
What I can also say from also posting this issue to a popular Facebook WRX group is that I'm not the only person having this exact same issue. Modded or not, other owners have experienced this same roughness/"bucking" problem in the same power band area.

[basyager]

Hard to say if same thing but right after getting etuned i noticed my exhaust “bubbles” a bit as in makes bubbling sounds and I can feel slight slight vibration from engine, car runs better when actually driving though. Tuner is 100% legit so conclusion is a slightly rough idle is no problem

[Knoxor]

Pull up your OVC (Oil control valve) data on the AP check they're all running about the same, I have the same problem right now and am about to try that. Sometimes they go funny. But I just realized I broke mine a bit when putting the engine back in.

[basyager]

Originally Posted by Knoxor

Pull up your OVC (Oil control valve) data on the AP check they're all running about the same, I have the same problem right now and am about to try that. Sometimes they go funny. But I just realized I broke mine a bit when putting the engine back in.

good advice, the vvti solenoids are known to cause rough idle

[Knoxor]

I just did a log on my OCV duty cycles, as you can see my right OCV is lagging behind, and if you look you can see a bunch of dips in the right OCV and if you look at my RPM its usually were my engine is trying to dip into idle.

I'm thinking this is my solution at least, I'll post an update once I replace it.

Also probably the reason I'm getting knock occasionally.

The Logs:

https://datazap.me/u/zknoxz/yeyeyeye...3751-3974-4237

[Knoxor]

Double post sorry.

[Sub2Grey]

Also try replacing the MAF sensor cable.


I had issues with my cobb MAF cable.



Similar symptoms with bucking and misfiring. AF correction would go 35+-


I like my AF correction to stay 25+-and below. It would seem intermittent like a short in the cable. Run right then go to shiiit and back.


I finally replaced the cable after troubleshooting and chasing the MAF and all kinds of other shiiit.

[desertrat505]

The culprit is the high IAT's. It wasn't happening in the cooler months was it?

[striktlysubie]

^ I'll keep some of the added suggestions about in mind (i.e. Oil Control Valve monitoring, and replacing the MAF sensor cable - my intake is from Grimmspeed with the heat shield box). As for IAT's, not really. Pretty sure I recall having this issue in winter also.

Also, some of my updates since the last post: To start troubleshooting what I already had lying around, I replaced the front O2 sensor with a brand new one a few weeks ago. It seemed to reduce the figure extremes that the "AF Correction 1" was reading before. However, the rough ride issue still intermittently remained. Anyone also notice that the problem I'm reporting may be more common at the constant speeds (as noted earlier), but also when going up a slight incline?

To add to the dilemmas, about a week after putting in the new O2 sensor, I was on the highway , and a CEL came on, "P219A" - "Oxygen sensors air-fuel ratio imbalance". This is a new one I've never seen before. Anyone with any new F'in ideas at this point??!

[striktlysubie]

I have to bump this again. So despite using the Accessport to clear the CEL for the newer "P219A" - "Oxygen sensors air-fuel ratio imbalance" code, it keeps coming back on. Also now, as of 2 days ago, my DAM reading is now sitting at .938, which I've never had before! I also feel like I'm getting some pretty big power and RPM swings when the new A/C compressor that the dealership installed last month kicks on and off. So, overall not sure what the heck is going on with this car. Getting frustrated.

[X49]

"Oxygen sensors air-fuel ratio imbalance" is probably due to your front and rear O2 sensor readings not being in agreement when the AFR is meant to be stoichiometric, where the rear narrow-band O2 is able to work.

The fact that the code started shortly after installing a new front O2 sensor leads me to believe that you may have replaced a good O2 sensor with a bad one, but I wouldn't completely rule out a bad rear O2 sensor. The fact that the issue occurs only at light to moderate throttle means that it is occuring when the rear O2 is controlling your AFRs, so it could be related to your driveability issues.

You need to add the AF Sensor to your datalogs. You also need to add Cylinder Roughness for all cylinders, which is a measure of misfiring. Post some new logs here and be sure to let us know the exact points in the log where you notice the driveability issues.

[H-Unit]

I went through a similar issue a couple weeks ago with my 2017 WRX and replaced my battery since there was corrosion on the posts and it ended up being a leaky battery. My issue seems to have gone away for the most part and is possible that your alternator is overworking causing your engine to be under more load than normal. Unfortunately I’m unsure whether the AFR would be effected other than maybe adding more fuel to try and keep the engine running?

[striktlysubie]

Still troubleshooting all this...

[striktlysubie]

Waiting on a new MAF extension cable from Grimmspeed to arrive...

[steagalarus]

Did you fix this?

[BlkWhtMagician]

I've been having the same issue I get a bank 2 running rich code P0175 that keeps coming back. I find the fact it says bank 2 hilarious because it only has one set of O2 sensors so bank 1 and 2 are read together. Still haven't figured out what's wrong and don't really have the money to spend on this car. Typically loss of power on acceleration to where it bogs down and tries to die. I've cleaned my maf, map, throttlebody, TGV system, did an injector cleaning, replaced spark plugs to which on the drivers side I found oil leaking onto the coil from the valve cover. While at work I've smoke tested the vehicle multiple times and I haven't found any air leaks. At this point I'm thinking about tuning the vehicle myself to try to get rid of this issue. Before anyone says it's the maf or map I've unplugged both while the vehicle is running and it just dies so it can't be the sensors. If you find out what the issue for yours is I look forward to hearing from you.

[striktlysubie]

Originally Posted by steagalarus

Did you fix this?

Not yet unfortunately. Still have the P219A code, and some fine knock issues at times. Blowing too much money on O2 sensors. Since the last post, I replaced the Grimmspeed MAF sensor harness, and cleaned the MAF sensor and intake filter, but there was no change. Going back to the tuner for other work (clutch is toast), so hoping they will figure this thing out also when it's plugged in.

[yamacheetah]

I'm no expert, but if you have large fluctions in AF correction also monitor the voltage going to the sensor and try cleaning the sensor. I'm not at all sure its the problem, but cleaning it is an easy possibility to check off the list and maybe replacing if needed.

[striktlysubie]

Originally Posted by yamacheetah

I'm no expert, but if you have large fluctions in AF correction also monitor the voltage going to the sensor and try cleaning the sensor. I'm not at all sure its the problem, but cleaning it is an easy possibility to check off the list and maybe replacing if needed.

Yes, trying all solutions we can think of. I had already cleaned the MAF and replaced the extension harness a while back, but that did nothing. I also occasionally get a fine knock CEL, which maybe also is electrical in nature. The car is still at the tuners getting repairs done, and when removing the spark plugs and coils, oil was found in all 4 plug cylinders!! Now getting all those gaskets, as well as the valve cover gaskets replaced. Not sure yet if this could have also been causing some or all of these driving and CEL issues. One thing after another...

[basyager]

you can spend another 2 years chasing the issue

or go back to stock and it will fix itself..

at least you will know if its a bug in the tune or the car itself..



Phatbotti troubleshoot FAQ has a lot of good info but nothing about P219A you were having.

[striktlysubie]

Originally Posted by basyager

you can spend another 2 years chasing the issue

or go back to stock and it will fix itself..

at least you will know if its a bug in the tune or the car itself..

That's an option, although not a very viable one right now. Although, we may ditch the catted Grimmspeed j-pipe and go back to stock to see if that does anything. Here's my latest scenario:

UPDATE: Still in need of help here, and very frustrated overall. So the car had massive service done at the tuner, and I got it back over the weekend. Based on all the issues found, repairs at 90k miles included: new MAF sensor, new front O2 sensor (now the 5th one), new knock sensor, new spark plugs and coil packs, fixed the oil leak with new valve cover gaskets, new clutch, and changed from top mount intercooler to FMIC. The tune was also redone and is reputable. We thought this would eliminate the pesky P219A code for "air/fuel ratio imbalance" for good, but once all readiness monitors were good to go after 2 days of driving, the CEL code came right back on again! I also then got a P0137 code ("Rear O2 sensor circuit low voltage" Typically caused by a failing or failed rear O2 sensor, a poor electrical connection on the rear O2 sensor, or damaged wiring between the rear O2 sensor and ECU"), which was not on before, and that sensor is fairly new, but then a day later that one turned off according to the Accessport code reader. I am at a complete loss. Does anyone have any other guesses as to what may be impacting the a/f reading? If this comes down to some wiring issue somewhere or a confused ECU, the diagnostics and labor alone might be a complete nightmare. I am now also overdue for my state inspection.