Hi, my check engine light recently lit up on my 06 Charger (2.7 v6 74k miles) so i had my mechanic run a small diagnostic cause I was getting a shake while the car was in park that gave me a bad feeling, so after he ran the diagnostic it came back with the code P0300 misfire cyl.#3, so I change all my spark plugs to be safe but the code kept coming up, so i ordered and replaced the ignition coil for that #3 but that just made the shaking worst, i honestly don't know what could be causing the issue, is there something i miss checking? don't want to drive and be over charged by the local dealer for something my mechanic can fix, btw I'm new to this, thanks in advance.