Audi A3 engine problem - doing my head in!

[kjhbigv]

Hi, Has anyone got any ideas about this?

I have a 2003 Audi A3 2.0 FSI with just 27k on clock.

About 1 month ago after driving about 150 miles the engine started losing power, as if one cylinder was not firing, eventually I linped to an Audi garage and they could not find anything immediately wrong on diagnostics APART FROM a melted spark plug core tip! Obviously, this was causing it to run on 3 cylinders! They replaced the spark plug and off I went, on my merry way.

The car was fine for a few weeks, yes I know I should have had it investigated but Audi main dealer 'investigating'!? Cost would have been, 'how long is a piece of string'?

Then a few days ago I was on another long journey and same/similar thing started happening, engine lost power almost completely. If I stopped and let it cool down, it would run again almost perfectly for 10 mins or so, then same thing, no power.

So, basically, it only happens when on a long journey and is obviously getting hot, something starts 'breaking down' and I end up with no power at all. It seems to happen quicker if I am doing over 70mph for extended periods of time!?

Any ideas anyone? Would really be appreciated!! It's starting to do my head in and I just can not rely on it for doing long journeys!

Thanks

[Dr G]

Well, if the mixture was very, very lean the combustion temperature would soar; which could explain your melted plug. What sort of colour are the tips?

The cause of lean running could be anything, lambda, knock sensor, AFM...

[kjhbigv]

Hi, need to check the colour of the spark plug tip and will report back.

I was thinking that it was running lean...not that I am an expert or anything but understand the principles of an engine.

Also, I understand that on an A3 each cylinder is effectively separate from each other and managed separately.

Someone did mention that it could be either the fuel injector for that cylinder, but surely it would run badly straight away?!

Dr G,

That is true if it was running lean the temperature would soar, but would that not happen immediately or over a longer journey? If I go out and start it now, it will fire on all cylinders and rev perfectly normally!? So that would indicate that this time the spark plug is ok! I would go and take the plugs out but unfortunately my leg is in plaster after saving another car....long story!

Edited by kjhbigv on Friday 26th October 15:18

Edited by kjhbigv on Friday 26th October 15:19

[Dr G]

kjhbigv said:

Also, I understand that on an A3 each cylinder is effectively separate from each other and managed separately.

Only in that each has its own coil pack.

kjhbigv said:

That is true if it was running lean the temperature would soar, but would that not happen immediately or over a longer journey? If I go out and start it now, it will fire on all cylinders and rev perfectly normally!? So that would indicate that this time the spark plug is ok! I would go and take the plugs out but unfortunately my leg is in plaster after saving another car....long story!

Cold start enrchment I would guess.

If I'm wrong then at least it's something we know that's not causing it.