Here's how to fix all the problems you'll run into with anything that zips.

VW Golf R Mk7 most common problems Excessive oil consumption – Issues with the car’s PCV could result in rear crank case seals to fail, but regular valve changes should stop this happening.

It could be an intermittent problem — meaning it doesn’t happen all the time — and it could apply to more than one cylinder. But what exactly causes a misfire?