Cylinder 3 misfire

[jrdnhsnbrg]

Well, Mary is borked again. I had to drive my car from my university to home this morning, which is about 40 miles of highway. When I started my car at school I noticed it was idling really rough so I grabbed my code reader and I'm getting P0303, cylinder 3 misfire. I replaced all the spark plugs with Motorcraft plugs 4k miles ago and all the ignition coils with Summit Racing coils at the same time, roughly 4k miles and 3 months ago. Any idea what could've gone wrong here?

 

[MooJohn]

I also had one of my Summit coils from earlier this year start acting up last weekend. I didn't have time to troubleshoot so I just tossed in one of the original coils (I kept them just in case) and the problem quit. It would be a shame if the Summit coils turn out to be junk; I did a fair amount of research on them before purchasing and all the owners seemed to be happy with them.

 

[jrdnhsnbrg]

I really hope that's all it is, I'll be taking a look at it in the morning. When I pulled in the garage and popped the hood there was faint smoke coming from the engine.

 

[jrdnhsnbrg]

Replaced the coil with a spare Summit Racing one I had, that was the problem. I'll be contacting Summit Racing about this.