08 a3 glowplug fault is it related to high idle revs?

mobirl

Put a 1.9 tdi through vagcom diagnostics and it came back with a glow plug fault in cylinder 2 as the only engine issue, that wasn't while the engine was running in case that matters. I was wondering if it might explain while idling it will creep up to around 1000 revs from 800 or so then drop if you rev it before repeating

George Dalton

It won't be anything to do with the glow plug fault but I have seen loads of them idle a bit high when the fuel filter needs changing. So change that first and see if it helps.

mobirl

A faulty lambda sensor was also mentioned as a cause where the engine thinks its cold but isn't. Does that sound likely?

If its an oil filter would it just be down to luck of the draw or a sign of other issues elsewhere?

George Dalton

There is no lambda sensor on the 1.9TDI but a faulty coolant temperature sensor can also cause a high idle, will usually log a fault code though.

If the fuel filter cures the problem then it is probably just a sign that it needed changing, I wouldn't get too worried or start reading anything else into it.