Anyone know how to tell whether your car is over-fuelling?

I know about looking at the soot on the exhaust (but how do you know what's normal?) and I suppose fuel consumption.

Any other tests/indicators?

Cheers.

Adrian.

Soot deposits on spark plugs.

Adrian, Myself and my mate Dave have noticed this, but given I am getting on average 33mpg on a work journey and 38mpg on an 85mph run I am not worried.

Soot is normal if you do shortish journeys and a grey exhaust if you do mainly longer ones where the engine is at operating temperature for most of the journey.

I was just wondering as my fuel consumption seems to be really bad of late.

Usually I can get 40mpg on the motorway and am struggling to get even 35mpg. My route to work I could get 35mpg and can get 32-33mpg now.

Maybe I'm just enjoying the remap etc too much.

Car is booked in for it's first service in a couple of weeks, got 20.5k now and still no indicator, so hopefully that will make a difference. That or I have to take off the lead boots.

If you've got 20.5K, Adrian, you have overshot your first service. Get the dealer to check why there was no warning of the need for a service.

I booked the car in at 19.5k a couple of weeks ago but couldn't get a booking until 16/10.

I don't think the indicator will come on unless the car thinks it needs servicing but as you have mentioned previously the owner should book in if 20k miles or 2 years has been reached regardless of the indicator.

Previously had service manager check the indicator at 10k as I was told that mine was on fixed servicing but no indicator came on. Will ask them to check it again anyway.