TJG you still got problems with the oil light?
Nope took the negative terminal off battery and it went, why's that?
Was thinking blocked sump strainer? 
http://www.audi-forums.com/audi-a3-rs3-s3-forum/45278-advice-please.html
Might be worth a look?
This self same problem came into my mates garage, guy had bought an audi 1.8T only 40k i owner ect ect just 4 years old. he said it sounded rough, oil light was on ect, just had fully synthetic oil 2000 miles ago.
droped the sump and the strainer was blocked with what he can only describe as gummy sludge. said it took 3 hours just to clean the sump pan out. fitted new oil pump and the engine was fine. but he did recomend
another oil change in 2000 miles so the synthetic oil can clean more of the gum off inside the engine. also warned the guy that the oil feed pipe to the turbo is small bore and will no dout contain some gum and should also be replaced. no point knackering the turbo! also he said to me, thing is in this situation the car has had some Sh!te oil. the oil pressure would have droped over time as it slowly gummed up. oil pressure light only needs 10psi to go out, yet the engine should make 60psi oil pressure. how long was it being raged around on 20psi pressure or less with the oil light out you thinking everything was ok.
It dosnt mean everyone has to go and drop there sump to check the strainer. but an oil pressure gauge might be a god idea, as you would see any pressure drop before the oil light comes on.
one good thing about main dealer service history! they wont fill your dub up with Sh!te oil. but a local garage useing cheap 20/50 mineral based oil while charging for high Q oil dosnt care.
oil pressure gauge anyone?
I asked why at 40k it was so bad, he said proberly not serviced by main dealer, which although the book was stamped it wasnt main dealer stamped. also the grade of oil used before was proberly cheap mineral oil which does sludge up quickly in modern turbo engines. he said the new synthetic oil had been doing its job, it will clean the engine and losen the gummy deposits in the engine. which collected in the sump and got sucked up by the oil strainer
