My prius is a 2012, with 125k miles. It recently started misfiring but only when accelerating slowly. It has the code P0302. I've already replaced the plugs and ignition coils, and cleaned the intake manifold with no luck. I dont think its the head gasket because my oil looks fine still. I'm thinking fuel injector cleaning next but open to suggestions
Once the head gasket starts leaking EGR cleaning is not going to turn back the clock. Try leskdown test and/or boroscope inspection of the cylinders, with cooling system pressurized. My 2cents, EGR cleaning, of the whole system, needs doing every 50k.
My oil looked great with the head gasket taking on decent water almost rolling the number two piston over and it's bore as it upside down and looked even new after the center girdle or block cracked I have a picture of it sitting in my yard everything was looking beautiful internally as far as the oil goes It was just making a racket because the number 2 rod broke at the small end and the crank was still available to spin at full speed and just the very tip of the rod was smacking on the end that was hanging out of the bottom of the piston which was now stuck at the bottom of its travel probably a little more down than it's allowable travel and that's what was hitting every time the crank went around so you got this dink dink dink dink sound.
