Subaru Impreza misfire problems

Filed Mar 4, 2026 · Transmission · TX

I own a 2024 Subaru Impreza (base trim, FB24 engine). The engine has developed repeated oil leaks into the spark plug wells due to failed spark plug tube seals / valve cover sealing on the same engine. The first occurrence was around 24,000 miles. The dealer found engine oil in the spark plug tubes, diagnosed leaking spark plug tube seals (and/or valve cover gasket), and performed repairs under warranty. At that time, the car was relatively new and maintained on schedule. The second occurrence happened again around 30,000 miles. The dealer again found oil in the spark plug tubes, indicating repeat failure of the same type of seals on this low‑mileage engine. This has already happened twice within approximately 6,000 miles on a 2024 vehicle. Oil in the spark plug tubes can cause misfires, rough running, and potential damage to ignition coils and the catalytic converter. It also raises concerns about stalling or loss of power if the misfires worsen while driving. I am concerned that this may be a systemic defect in the FB‑series engines used in late‑model Subaru vehicles, not normal wear. I am requesting that the federal safety agency track this issue as a potential safety‑related defect involving engine sealing components (spark plug tube seals / valve cover gaskets) that allow engine oil to leak into the spark plug wells on 2024 Subaru Impreza models at low mileage.

Filed Sep 19, 2022 · Brakes · VT

Suspected defective and/or faulty brake booster or brake hose on the front left tire. Car starts violently shaking/shuddering when easing onto the brakes (once the brakes have warmed up for my daily commute to work). Resulting vibrations travel up the steering column to the steering wheel, and into the cabin. The car will then pitch its nose in various directions; it feels as though the front left brake is being grabbed and not properly released. Taken to a Subaru dealership multiple times. New brakes and rotors installed in July 2022; other components of the brake (calipers, pistons) were inspected in Aug. 2022 and appeared fine. However, on inspection (08/2022) the newly replaced rotor on the front left tire was already showing visible wear/damage (white scalding) due to excessive heat generated while braking. I have taken the car to be serviced at a dealership multiple times & have been told the shaking "couldn't be replicated." I recreate it every day I drive to work (350 miles every week). *Please* see the video linked to a third-party website: https://imgur.com/a/wFvLV0A Other symptoms: The engine starts and runs roughly despite recent oil changes. OBDII code P0300 (Random/multiple cylinder misfire detected) was detected by a personal OBDII scanner, although I don’t know if that issue is related. Ignition timing advance for the 1st cylinder is near red zone. Please help..

Filed Jul 20, 2020 · Engine · 200,100 miles · NY

Hard start, rough idle, drove 3 miles, check engine light turns on, code: p0021 bank1/2. Did research. It's a banjo bolt filter/screen mine was cracked in half inside the oil line restricting oil to the turbo. Managed to remove one easily accessible banjo screen which fixed half the problem. The other bolt virtually not accessible by me. Almost all turbo vehicles from subaru experience this problem as code: p0021 or just catastrophic turbo/engine/coolant failure.

Filed Apr 1, 2020 · Engine · 120,000 miles · NM

I have been experiencing a rattling noise accompanied by loss of power and a rough idle at low speeds. I thought it mught be the idler pulley--replaced that along with the serpentine belt and tensioner. Did not fix the problems. Yesterday it began to stall at idle and low speeds. Car will not start. Symptoms match those related to the wty 84r bulletin and the 18v772-7070 recall for broken valve springs but the dealership says my vehicle is not in the VIN range. The car is a 2012 impreza--the problem matches the problems for the 2012 impreza.

Filed Sep 30, 2013 · Engine · 129,000 miles · NJ

Purchased car august 20th. August 24th, 2013 on the way back from pa on 80 east my check engine light came on. Problem was diagnosed as cam position timing over advance or system performance b1 and b2. Code was p0011 and p0021. Wednesday september 11th, 2013 the car was taken to subaru world of newton to be fixed. Needed new cam sprockets and timing belt, along with the timing belt the timing belt tensioner was changed and a small oil leak was plugged with an oil change. That all came out to around 1,500 and that was after negotiating. Monday september 16th, 2013 my check engine light came on and with it had rough idling. Thursday september 19th, 2013 I had the code read and the code p0301 came up which was a cylinder 1 misfire. The code was reset to see if it would reoccur and tuesday september 24th, 2013 the check engine came back on with the same code. I then planned on going to subaru world of newton on saturday the 28th. On friday the 27th I was driving to the mall in rockaway, nj 20 minutes from my house and I started to feel power loss. On the way home from the mall the power loss continued and about 30 seconds from the sparta exit my engine made a knocking noise like something sprung loose and my engine cut off and the car shut off, with no power steering I had to get across the lanes to pull over and wait for a tow truck. Today september 30th the car is sitting at subaru because the diagnostic fee 1-2,000$ and approximate cost for parts and labor is 5-7,000$, total is 6-9,000$.

Filed Jun 23, 2013 · Engine · 35,000 miles · VA

Cracked piston, cylinder 2 misfire.

Filed Mar 4, 2009 · Engine · 12,500 miles · NJ

Smoke coming from the exhaust, rough idle, oil consumption were my first signs. The dealer wouldn't do a compression check on the motor since there was no check engine light on, so I had to pay with my own cash and take it to a private shop and found out that in fact cylinder #2 had a shot ringland. They replaced the piston but the motor doesn't seem to be right still since I have a car that was involved in a "stop sale" that involved some engines having some debris in the motor and was causing knocking and throwing bearings. Subaru should have replaced the short block but didn't.

Filed Jun 9, 2003 · Engine · WV

When driving vehicle begins to vibrate and then drastically loses power not being able to maintain speed above 40mph. Dealer has diagnosed problem as a misfire on cylinder 2, but has been unable to correct.

Filed Aug 24, 2002 · Acceleration · WI

After the first oil change noticed a hesitation problem when acellerating form a stop and a rough idle. This happens after the engine is warmed up. Reported the problem to the dealer they said they did not know how to fix it. Contacted subaru directly and they denied any knowledge of this problem. Found out form other people that this is a known problem. It is not getting any better and am worried when I take off some time that if the engines stalls out like this I could get rear ended.

Filed Mar 22, 2002 · Engine · VT

Slight engine hesitation; refer to tsb#115398 in mt 1/99; is this a problem they have not resolved....fearing potential accident if it gets worse; also engine misfiring which may result in cylinder failure and loss of power. Manufacturer not repairing and in denial of all requests...three failed repair attempts.