My mate has got a Mk2 FRS and when on boost between 4500-5000 RPM has a little misfire/shudder and then clears.

I suggested to him to change the plugs on it as the first thing to try.

The car is standard at the moment.

What are the best plugs to stick in it?

Cheers people!

 

I would say genuine ford.

What milage has it done, when I replaced my mates plugs on his focus st they were in good condition after around 45000miles

 

It's only done just over 16k but it could still be an iffy plug.

Cheapest option to try first!

 

Genuine Ford i had a missfire @ 8000 miles changed the plugs and job done