Irregular idle, bouncing revs... Help?

[fortunateson09]

Hi all. Not a forum regular, so apologies if this has been done before...

During the hilariously wet weather a few days ago my 2003 2.0hdi had a bit of an excursion into a pretty deep (6-8inches?) puddle.

Drove the short distance home without noticing ill effects, but when I came to drive it the next day, it wasn't too keen to start and is now exhibiting a pretty uneasy idle, even dropping to a stall a couple of times.
It's no better when up to speed, with very 'bouncy' revs and feels like it might be down on power, but it's so lumpy it's quite difficult to tell. Very occasional flash of the engine warning light too.

Any ideas/ suggestions? I'm thinking it could be an electrical/ injection issue? Or maybe a soggy air filter? I've not had a chance to have a proper poke around yet. Anything you think I should be looking out for?

Many thanks.

[Lighty]

Personally I would check the air filter before further use, it could be flooded.
If not, then probably water in the electrical blocks, or even the ECU connectors.

[fortunateson09]

After fairly extensive poking around and diagnostics, this was tracked down to a faulty ECU. Now to track one of those down...