[Roberto67]

Hi all I'm glad to join,

I love my i30 it's done 60 k full service history over the last week its had a first issue since I had it .he juddered between 30-40mph.

Since then it's got worse I plugged it in and I got cylinder 4 misfire it's not all the time. I am hopping iam correct I am going to change the spark plugs and all four ignition coils as I read up they can go.around this mileage. Happens not all the time just randomly.. I think cylinder 4 ignition coil may have weak spark?

Am I barking up the wrong tree or is this a good first step .

[Aye30]

Hi, you could swap plug  4 and coil 4 with  position 1 plug and coil and see if the misfire moves. Thus ensuring combo is the cause. You could also swap coil vs plug positions, to see if it could just need new plugs. Just  a thought.