2018 RX450h P0306 cylinder 6 misfiring

[darrenpfd]

Hey all! first post, so hello 🙂

I got the subject error come up a few months ago. A bit of googling suggested that I changed the spark plug in cylinder 6 (rightmost plug, front of engine) which I did. The issue was seemingly cured for a week or so, then came back with the new spark plug fitted, but where it was quick and constant with the old plug for it to appear, it now only comes up on heavy load of the accelerator.

With the cold mornings we've had it's been a bit lumpy to start but settles down after a minute or two. No change in MPG. No smoke out of the exhaust other than what happens normally at initial start up.

The engine coolant reservoir is still full and pink, so no loss of coolant or mixture of oil that I can see.

The previous spark plug was pretty filthy; rust or burnt metal up to and around the nut. Checked this one today and it looks fine. 

Pretty stumped. Anyone have any ideas? 

[Spock66]

Possibly the coil pack.

[katabrontes]

Almost certainly the coil.  I have the same problem with my 350 all fixed with a replaced coil.  Mine had warning lights coming on and a fault code as well.

[darrenpfd]

Thank you for your replies. New coil sorted the issue 👍