I have a 2008 Toyota RAV4 2.4L that I recently had the spark plugs changed on them after the check engine light came on with code P0303. About a week later and after driving about 200 miles the engine starts really weird after it’s been sitting overnight. The car idles and drives fine but upon first start up it has this engine shake. I attached a video of the cold engine starting up after sitting overnight.
https://youtube.com/shorts/EYAv8P26yHA?si=9ipmm3uzQ1upOwBX
Well, if all this happened after you change the spark plugs either the number three ignition coil assembly was damaged. Realize they're plastic and twisting and taking them out to replace the spark plug and often damage them, or, the connector for the coil isn't on tight. If you unplugged it to get it off, you might not have snapped it back on type. Of course, I'm assuming the only thing you did was change the spark plugs and didn't touch anything else and break a vacuum line or disconnect some wire somewhere
