SOLVED: Engine cylinder 4 Misfire P0304 NEED HELP!

[m3gang]

Hi fellow enthusiasts,
Car throws CHECK ENGINE light. iDrive says increase emissions. Used a scanner and throw code P0304 misfire cylinder 4. Car runs rough on idle but smooth once warmed up or after cold start cycle ends. No limp mode driven for 15 miles. Any idea on what might cause this would be greatly appreciated!

[vm]

Originally Posted by m3gang

Hi fellow enthusiasts,
Car throws CHECK ENGINE light. iDrive says increase emissions. Used a scanner and throw code P0304 misfire cylinder 4. Car runs rough on idle but smooth once warmed up or after cold start cycle ends. No limp mode driven for 15 miles. Any idea on what might cause this would be greatly appreciated!

Bad coil and/or spark plug. Much lower probability a broken valve spring.

[m3gang]

Just changed spark plugs today. Last time spark plugs was changed was around 28k miles. Now car has around 98k miles. 70k miles on a set of spark plugs definitely isn't a good idea. After spark plugs change engine runs super smooth and no more problems at all. Definitely going to doing more regular spark plugs change from now on. Hopefully this thread help some people figure out their cylinder misfire issue. Thanks vm for the reply.