2011 chevy 1500 code P0304

[chevy4x4dig]

I have a 2011 chevy silverado 1500 that was acting normal but now it out of whack. Recently the traction control light says its off and on the display reading it says service traction control and service stabiltrack. Also my check engine light is blinking and dinging. The engine sounds rough and and when the tranny shifts down, it shifts hard. I hooked the truck up to a code reader and it came up with a code P0304 which is a misfire in cylinder 4. I already replaced the spark plug, plug wire, and coil. None of this fixed it.

 

I did some looking around and I have read that the throttle position sensor could be wrong on this. But I'm looking for some more advice. I just recently bought this truck used so idk if that has been replaced before. I know there was a recall on them before. The truck has around 95,000 miles on it. Any help would be greatly appreciated. Thanks.

[Sierra in the Sand]

How's your oil pressure? Mine (09) started throwing misfire codes and had to have the Fn AFM lifters replaced, still had the same problem, then the oil pressure went really low. Turns out the lifters won't switch without good pressure, and will cause misfires.