My engine has been running rough lately. Occasionally, especially when it is raining and/or cold, the idle starts to dip below 500 and the car acts very jerky. Additionally, the car's power seems to come and go. Occasionally I get the check engine code for a cylinder 2 misfire.

I was thinking this was related to a bad coilpack and wiring, however lately it also happens when I step on the brake hard to a stop.

Is it possible that there are two unrelated problems going on, or should I just replace the coilpacks? Brake booster vacuum leak?

Should I just buy the cylinder 2 coilpack and see if that resolves the issue?The spark plugs should be fine and I put in a new knock sensor a month ago and that didn't hurt or help the problem.

 

Similar problem - RPMs dip close to 500 and it starts missing. IMO its nothing with your brake, its just that you are coming to a stop and idling at low RPMs.
How about swapping coil 2 with 4? Its the front pack, literally 5 minute job. See if the misfire travels with the coil.
Also, the FSM mentions the coils if you particularly notice it in damp weather. Hope it helps.

 

Hey thanks for response. Ill check it out later this week when I get some free time!