Hi,bought a 2000 3litre petrol V6 S-type six months ago returning around 27 mpg but has dropped to 20! 2nd car used for distance runs mainly. Recent new plugs and coils to cure misfire. Starts on the button and runs well, no fuel leaks/smells. Can you advise please? Many thanks, Steve T.

check that the rebuilt box is actually engaging OD. Run fault codes and check it electronically. Have the bands and clutch packs re adjusted as the run in may have put the adjustment out a bit..

Check and see if your e brake is dragging sometimes Rust build ups create friction w drums or try changing your differential gear oil

The Fuel Economy of the 2004 Hyundai Santa Fe is listed as being 16 mpg in the city and 22 mpg on the highway.----------------------------------------------------------------------------------
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If you want fuel economy then dump this beast and buy a nice peugeot or citreon picasso diesel manual then you will get around 30 mpg around town and anything up to 70 mpg on a run ,try paying our fuel prices and this nice typical american petrol gas burner would be delegated to the classic car sunday drive out like my jag with its 4lt engine i can only afford to take it out once a month or so on a jaguar club run around ,other than that its my ford diesel manual escort with its 0 to 60 in 15 minutes but it only uses one tank of fuel a month.

When was last tune up? Plugs, wires, all fluids & filters? Especially fuel filter? I'd start there and run a good fuel system cleaner through it.

Hard to say on a older car such as this. If running well and healthly it should receive around 16 to 18 highway miles per gallon

Is the engine running at the correct operating temperature? If the thermostat is stuck open or opening too soon it can have a really negative effect on fuel mileage.

it sound like your tps is going out

Make sure the vehicle has had a tune up, Spark plugs and wires. Check PCV valve. ETC. ALso may want to run diags on it with OBD code reader to see if it is pulling codes that just arent' showing on CEL(Check engine light)

Doubtful. The K&N air filter is an aftermarket part which isn't compliant with standard factory parts against which those recommended MPG are tested.

The tyre pressure sounds too high for a car that size also, it would be worth enquiring with a main dealer what the reccomended pressure is.

Also your own driving ability comes into equasion too. Heavy/constant braking can affect it, having the air con witched on affects it etc etc.

All of the above combined would make a pretty big difference to your MPG.