Hi guys, new the forum

Wondering if anyone can shed some light on the problem im having with my MK4 SE Golf. I purchased it 2 weeks ago from a dealer (so its still under warrenty) and now its misfiring when idiling. Drops to about 800 RPM at traffic lights, and recently had a seroius misfire when driving around.

The garage has picked the car up and is currently being fixed but im wondering if anyone can give me some advice if there is anything else to look out for ? The garage said it was sticky valve but i find that hard to belive if it was misfiring while driving normally, (i might be wrong). Then the engine warning light came on and started flashing at me.
The car drove fantasticly before the misfire, this was just before i done 2 hours motorway driving. I hope my golf is okay, its my second car that saved for ages for ! Any help would be greatly appreicated !

I forgot to add that the car has a full service history from Volkswagen, and is currently on 70,000 miles.

Thankyou

 

ive seen corrosion on the coil cause the same thing