2005 g35 coupe
Hey guys so my car has felt a little sluggish but runs very smooth. Lately it has begun misfiring only at idle in drive, like when at a red light. No check engine lights come on. I went WOT the other day and felt a hard miss, check engine light blinked a few times and went off. Checked the code, got P0301 Cylinder 1 misfire, and saw it could be many different things.

I changed all the spark plugs last summer and the car runs good otherwise. Is it more than likely the Cylinder 1 coil pack, or what should I be looking at?

 

Start by removing the plug, I have a strong feeling you're going to find oil in that spark plug tube well. If you don't find oil and the plug looks fine go ahead and replace that coil pack with another hitachi unit.

Or if you don't find oil you can swap that coil with the one next to it and see if the code switches to P0303.

 

when I changed the plugs I had oil in cylinder 6 I believe (passenger side farthest back towards fire wall) but no other cylinders. I was told I needed a new valve cover, that it would keep the oil from getting into the plug well is that correct?

Ill try swapping the coil packs when I get time

 

Yes when you're leaking in the cylinder wells it's a "non removable" seal in the valve cover that's failing. There is a way to replace the seals without buying new VCs you can find some threads on it with a google search.

 

Rockauto has new valve covers for I think around $30 so I'll probably end up picking up one of those sooner or later.

I swapped the coil pack this evening for a new one, car feels great now, it must have just been on its way out where it was acting up bad enough to miss but not enough to throw a CEL.

Cars running great again. Now for the wheel bearing and upper control arm this weekend.. been procrastinating on that like a MF, bearing noise has gotten super loud. Definitely doing it this weekend.

As always thank you for the help Cleric you're the man.

 

Rockauto has new valve covers for I think around $30 so I'll probably end up picking up one of those sooner or later.

I swapped the coil pack this evening for a new one, car feels great now, it must have just been on its way out where it was acting up bad enough to miss but not enough to throw a CEL.

Cars running great again. Now for the wheel bearing and upper control arm this weekend.. been procrastinating on that like a MF, bearing noise has gotten super loud. Definitely doing it this weekend.

As always thank you for the help Cleric you're the man.