Hello, I am the owner of a 2011 Toyota Prius II with 166,000 miles on it. I have recently had the the fuel injectors and spark plugs (not me, a mechanic) replaced. While the car mainly runs fine, the ICE (the gas engine, not the electric) has developed a tendency to shake for a second or so before firing normally. The CEL (check engine light) is not on, and it tends to happen in lower torque situations. I had the transmission fluid flushed six months ago, but have not flushed the coolant. Does anyone have any idea what could cause this and what the solution would be?
Typically its a head gasket leak after the normal plugs and injectors have been done. Eventually it will start losing coolant but that can take months. Shutter video
Leak-down test will confirm if it’s head gasket failure. With 166k miles and (presumably) no Exhaust Gas Recirculation cleaning, it’s likely. And Toyota keeps quiet. Thread by @The Critic on his head gasket replacement and head rebuild: 2011 Prius Head Gasket Failure | PriusChat Info on Exhaust Gas Recirculation cleaning: Bad Flywheel | PriusChat
See also: "Prius Death Rattle" Things YOU can check If you do not do your own maintenance: Check the oil....look for (and smell for) coolant. Check the ICE coolant level in the coolant reservoir. It's possible that you're in the very early stages of head gasket failure, and you need to immediately address this to prevent (more) significant engine damage. Good Luck!
