Hello,
Figured I’d shoot my shot here and see if there’s any knowledge on a Prius. I have a 2012 Toyota Prius with 196k miles on it. Upon SOME cold starts, when I cut the car on, the engine will turn on and run rough (knocking/shaking/shuddering noise happens). Originally, the code P0302 would come up. I changed the spark plugs and coil packs hoping that would fix it, however it has returned every now and again. The code is currently gone, but the shuddering still occurs sometimes. It dissipated after ~5 seconds and the car works as normal afterwards. I took the car to read the code and it says cylinder 2 misfire, with cylinder 3 and 4 misfires also detected. Blown head gasket?
I had a friend with similar symptoms on that generation Prius.
They never found the exact cause, and it hardly happens, but happens now and then.
When doing research at the time, one theory that popped up was condensation in the intake.
If you do find out what it is, let us know!
When was the fuel filter last changed, or ever, in 196,000 miles?
