1.0 Tsi 3 cylinder in a mk3 Fabia. 2018 reg with 110,000 miles.

It's run perfectly for 4 years until last week when it started misfiring when under heavy load. Cleared all the codes and drove it. Code p303 came up, misfire on cylinder 3. I swapped the coil packs over between cylinders 2 and 3 and went for another test drive. No misfire and no fault codes. Very odd. There was a bit of oily mess on the boot on pack 3. Could that have been the issue? Or will it come back? Is it worth replacing the coil packs?

Check the spark plugs as a first step.

3 hours ago, Breezy_Pete said:

Check the spark plugs as a first step.

Swapping two coil packs over fixed it, so I doubt the plugs are the issue. I think I'll replace the coil packs, since their claimed life expectancy is 100,000 miles, with some lasting out to 140,000 from the reports I've seen.