mpg fallen drastically

[chips]

Hi there everyone

I have a 2001 Passat 1.8 20v non turbo 67k miles. The past 2 weeks or so I have noticed that my mpg has fallen dramatically, its down to about 15mpg around town and not much more, about 19, 20mpg on a longer run, say 60 or 80 mile trip carriage way/b roads. There doesn't seem to be any lack of power or anything else I can associate with it. I have checked the plugs, they were fine but changed them anyway, air filter and fuel filter were changed not so long ago, along with oil filter.

I have check for faults with vag com(shareware) but there are no fault codes. I did have to change the oil cooler just before christmas, and did have the battery disconnected for a couple of days, and I have read about the throttle bodies needing calibrated after the battery is disconnected. Does anyone think this maybe the problem, if so, how is it rectified, or does anyone have any other suggestions as to why my MPG has fallen so horribly. Any thoughts or advice on this would be greatly appreciated as 60-80 miles to £20 isn't very pleasing.

Thanks everyone



Chips

[KeithS]

Check your brakes aren't binding?

[chips]

Hi

Thanks for the suggestion.

I changed the front pads yesterday, and she rolled easy enough before that, I also looked for any leaks from the tank, filter and fuel lines. All were clear. I don't think its the cat either as there is no smells from the exhaust. One other thing, when I was out today with vag com, the tank reading started at 25.1lt, and by the time I was finnished about 45 mins just on tickover, the reading had went down to 24.1lt is this normal ?

Thanks for the reply, and keep the suggestions coming.



Chips

[paulthefox]

did u check your maf by any chance;) it can cause the problems u describe


paul

[chips]

Hi

Thanks for the suggestion, I'll check the MAF tomorrow.



Thanks



Chips

[chips]

Hi all

Me again, I checked my MAF senor, but it was clean, there was very little of anything around it, I gave it a bit of a clean anyway with some pcb cleaner. Is there any way to check the MAF to see if it is giving the right readings. Does anyone know the voltage ranges it should be outputing, or anyway to test them. There is no other MAF related effects, my acceleration is smooth, no lumpy tick over, and no flat spots. I know I do mostly town driving, but the car has been returning better fuel economy than this, and I do look after it. The plugs are a nice light grey colour, air fuel and oil filters were changed not so long ago. If anyone can suggest anything else to look for I would greatly appreciate it.


Many thanks all


Yoinker.

[chips]

Hi all

Just to let you all know, looks like it was the MAF sensor:D. MPG is back up and the car even feels better to drive. Thanks for all the help.:beerchug:



Chips

[colin916]

Also, for anyone else with this problem, check the vacuum pipe under the intake manifold. I had a 2000 w model and the pipe was perished. A repair made a startling difference in mpg.