2010 Prius base, 225,000 miles odometer reading. When it's freezing, the car will stutter and shake violently at cold start, sometimes throwing P0303, occasionally P0301. Stutter continues for a minute or so, then it works normally. Lots of fog from tailpipe during the "stutter" phase. Oddly enough, if at first stutter I turn the car off and back on, it decreases the "shaky warmup" time significantly. When it's extremely cold, the engine shakes like an RUD event is imminent, then CEL comes on along with a P0300+P0301+P0303. Once warmed up, car operates normally… with a small caveat. Whatever causes that stutter, manages to freeze again in a few minutes (or sometimes even seconds), for example while waiting on a long traffic light or a railroad crossing. Tap the gas pedal and… Brrt pfft, shake your booty! The colder it gets, the worse are the symptoms. I feel like it could really RUD on me when the outside temperatures get below 10F, so any help is much appreciated. I'm completely puzzled by this. It seems that whatever is causing the problem has a minimal heat capacity and are not directly connected to the engine, hence it freezes back to its "troublemaker" state rather rapidly, even while the rest of the engine is hot. …A few more details. I'm an Uber driver, so I drive a lot. About 200 miles a day on average. When these symptoms first manifested in late December, I cleaned the throttle body, intake manifold and EGR pipe (and changed a PCV valve while at it). It's really hard to tell if it helped, since around the same time the cold spell went away and it was warm here (above 32F) up until recently. While cleaning the intake manifold I had a chance to inspect the engine for any irregularities. Nothing seemed to be out of the ordinary, no gunked up injectors or unusual deposits. Spark plugs are good to go for at least 30K more. I haven't cleaned the EGR cooler yet (royal pain, but it's on my todo list). Haven't checked injectors for resistance either. Any ideas?