Well my brother Audi woes are still going on with his A3 and Audi are saying they can't find nor feel any problems with his car but he is insistant that there's still the odd hesitation/cough.
Anyway looking back through the service records there's actually some 'non everyday' stuff on there. Faulty knock sensor replaced, car was idling rough for example but I did notice that they found oil in the petrol tank but left it as it was in the end. I'm going to change the fuel filter and put some injector cleaner down as there's no records of the filter being changed but has anyone any idea how oil could have got into the petrol?

If it's in the tank surely it's gone through the filler?

Someone's filled it with a can that's had oil in it?

unless some previous owner has thought - ill put some fuel additive or similar thro the system to clean it - bought the wrong stuff?

take the tank off and clean it out

then put some fuel system cleaner through it

How did they diagnose it... did they empty the tank and test the fuel? No one's accidently put some diesel in there have they???

Also, is it an FSi engine? If so, then the coils are notorious for packing in and they do stutter before the spectacular fail!

I would think the only way for oil to get into the petrol would be for someone to put it into the tank. Depending on how much it would do no harm other than may be oil up the plugs and after a few tankfulls would be diluted anyway.
I run a Mazda RX7 as a trackday car and use 2 stroke mix to lubricate the rotors instead of the total loss standard system with no harmful effects. Too much would lower the octane rating of the petrol and maybe cause detonation.

quote:

---

Also, is it an FSi engine? If so, then the coils are notorious for packing in and they do stutter before the spectacular fail!

---