Not the obvious sort of fuel leak

[philj]

Fuel economy has gone from bad to very bad and there's a slight smell of fuel under the bonnet.

Had a look today, and the whole fuel system seems dry. Except it stinks of fresh petrol around the bulkhead end of the rocker cover. All the injectors are dry, as is the FPR and all the pipework to and from it and the rail. It's only smells when the car is running, and my nose says its not coming from the FPR, but under the coil pack cover?

Could a spark plug have come loose? Wouldn't that sound like a lack of compression on one cylinder?

[220bhp]

Is your car a ur s6 or s4. If so check the fuel filter connection. Its a braided fuel line.
Drivers side under bonnet at the back of the wing.

[philj]

Cheers for the suggestion. It is an S6, and I've followed all the pipes from where they come from under the car, to the fuel filter, braided hose, solid hoses, rail and injectors and the whole system seems dry and doesn't smell. It's only when the engine is running, and my nose says its not the FPR, or hoses to and from, but almost as if it is coming from under the coil pack cover.

[220bhp]

I have an s6, and the braided hose only leaked when the engine was running. then it got worse, and it leaked when the ignition was on, that's how I found it. I was told by Audi at the time its a common fault on the s6. I am not saying its your problem, only that it could be. I fixed mine with ptf, and it been fine for a good few years.
Good luck

[philj]

Look as if my braided hose has been replaced. Fixed it now anyway. Turns out all 5 spark plugs were loose.

[UrS4boy]

Look as if my braided hose has been replaced. Fixed it now anyway. Turns out all 5 spark plugs were loose.

FIVE?? Oh man. I guess I haven't been doing my job:

http://www.s2forum.com/forum/showthr...333#post780333

and specifically: http://forums.quattroworld.com/s4s6/msgs/3757.phtml

[philj]

All 5. Not one needed anymore than a little fingers torque to undo. Torqued to 24ft/lb, undone, and retorqued to 24. Apart from the smell of fuel, it seemed to drive fine. So how often do they need re torquing then? Never had an AAN for more than 2k miles, and it's not an issue I've ever come across on any other engine previously.

Take it the V8 doesn't spit it's spark plugs out?