Hello 310K KMs.. (195K Miles for US friends). Car shudders very noticeably/audibly when below 20KM/h on low battery, on 2 bars. Once battery charge is above 2 bars, the shudders reduce in intensity significantly but it is still there as long as ICE is running. I can tell because as soon as I drop into using electric engine only, car is fairly quiet. EGR was cleaned out as per previous owner. The low battery shudder was always there since I bought it earlier this year. The shudder at all times is recent. What are some /likely possibilities here?
Is the shudder worse when engine is cold? Are you having to add coolant regularly? Any check engine lights (error codes) or other symptoms?
No, the engine temp doesn't seem to matter regarding shuddering. Coolant levels are within threshold and not running low/refilled. No engine lights either
Intermittent shaking? Or consistent shaking when down to two bars? This points to issues with motor generator, but there hasn't been an issue at all with that part of the Prius since 2000-2003. Maybe @ChapmanF might have some input?
When it's at 2 bars and charging kicks in (40% approx) there is consistent shuddering unless I speed up enough like 30-40km/h. It's still there then but less.
then again, could it ne plugs/injectors/throttle body/o2 sensors? some things throw codes, others don't. i have read that when the head gasket first begins to leak, it doesn't lose any coolant
Back here you were saying it wasn't, at 191k when you acquired it: 2010 Prius Mileage Going Worse | PriusChat A moot point now I think. I would at least check the EGR pipe condition (goes between EGR valve and intake manifold, and the intake manifold itself. See top two links in my signature for more info. (on a phone turn it landscape to see signatures) That said, it sounds like head gasket. Are you keeping an eye on the coolant level in the engine reservoir? I'd also do a borescope inspection of the combustion chambers, day after driving, and preferably with engine coolant system pressurized, to accelerate any head gasket coolant leakage. If you're still reluctant to DIY (per the link above), it might be time to ditch it.
