Ignition coil issue?

[Jamina]

Anyone know what would cause this on an ignition coil.

MK4 golf is misfiring on cylinder 3. Pulled this out of the 3rd cylinder along left to right so assume this is the right one.

Certainly looks unwell?

[Jamina]

Ignition coils sit right under the oil filler, looks like overspill combined with bad seals on the ignition coils has fouled it.

Hopefully simple swap and more careful filling will resolve.

[Scott.T]

I doubt thats causing the issue.
I've seen alot worse when the cam cover seals around the spark plug bore fails and the spark plug/coil pack chamber is like a swimming pool of oil.

I expect if it's flagging a fault it's just a dead coilpack.
Does the idle change when you disconnect the electrical connection on this one.

My son's mini dropped a coil pack a few month ago, luckily on the drive. Swapped a new one in there from Euro Car Parts for about £40.

[Jamina]

Thanks @Scott.T

Misfiring has now stopped but rough idle, bad fuel economy, power surges and breathing difficulties.

MAP sensor was then flagged up, have replaced this but still no luck.

New fault flagged up as O2 sensor, reading through the symptoms this seems to tick all the boxes.

Will try this and see how it goes.

[Jamina]

No luck with the O2 sensor. No difference at all.

Next up was the EGR valve and it now appears to be running better than ever on idle, the state of the old valve would also confirm this needed a change.

Ran the car for 20 miles without issue. Last test was to throw a sudden drop in revs to see how the car coped (this would cause it to cut out when the issue started)

Got up to speed (empty road) dipped the clutch and took it out of gear and sure enough the sudden dip in revs caused the car to cut out.

It feels as though the sudden drop cuts the voltage in the car. Started back up, came to a stop and it had a rough idle again for about 2 minutes and then settled back to perfect running again.

Any suggestions on how to cure this?

[HYDROSCOBY]

Have you checked the air filter as it my be the car struggling to get air?

Only say this because I was chasing a boost leak and then found out it was the air intake issue

[Jamina]

Hadn't even crossed my mind but this is a good point - the air intake is integrated into the engine cover which sits right above the engine.

Always thought this cannot be a great design but then again lot's of old cars came with over the top air intakes - will investigate the state of the air filter later.

It's a 1.6 N/A so I guess they weren't too bothered about warm air strangling "performance"

[HYDROSCOBY]

Well hopefully you will find the problem out but always worth checking the basics first