I’ve been experiencing a subtle but annoying issue with my 2015 Volvo S60 T5 R-Design (2.0L Turbo, 245hp) and wanted to get your thoughts on it. I’ve done a lot of searching but still can’t quite pinpoint the cause.
Background:
- Mileage: 118,000 km (~73,000 miles)
- Engine: 2.0L Drive-E Turbo (245 hp, no mods)
- Fuel: 95 octane (as specified, but read on…)
- Recent Maintenance(done by previous owner):
- Timing belt replaced a few months ago
- New spark plugs and ignition coils installed
- Mechanic Inspection: Car checked out healthy overall. One engine mount is worn but “not critical” per the mechanic.
- Battery: Standard (non-AGM), start-stop occasionally reports it’s not functioning — expected with this type of battery.
The Issue:
Under heavy acceleration, especially as the RPMs climb above 4,000 or even less-, I sometimes feel what I can only describe as a slight jitter or soft misfire
it doesn’t happen in first gear,first gear pulls hard a smooth, only second (sometimes not) and upwards, which makes me think maybe it’s boost related issue
. It’s not violent but you can feel it, and it doesn’t happen all the time but when it does, it’s most noticeable at wide open throttle or aggressive pulls.
Additional symptoms:
- No check engine light
- Car otherwise runs great in normal driving
- Occasionally, after a hard driving session or long highway run, I’ll feel a slight jitter or roughness at idle, which goes away shortly after
- No overheating, fluid levels are fine, car drives smoothly otherwise
My Thoughts So Far:
- Spark plugs/coils are new, but I haven’t verified the plug gap or brand — possible issue under load?
- Fuel quality? I use 95 octane as recommended, but thinking of testing 98 octane for a couple tanks in case it’s knock/timing-related
- Worn engine mount could be causing movement under load
- Possible boost/vacuum leak? I haven’t done a smoke test yet
- MAF sensor might be slightly dirty or off
- Could a weak high-pressure fuel pump cause this kind of behavior only under heavy load?
- Battery is standard, not AGM — could voltage irregularities impact ignition or fueling?
Sidenote: I’d upload a video of the acceleration but you won’t notice anything, I mostly feel the car “jerking” really like a missfire
I’d love to hear from anyone who’s had similar symptoms or can weigh in on possible causes.
Thanks in advance — I really appreciate the help.