2.0 20v petrol "BAD" fuel consumption

[TheDervDoctor]

Hey i own a passat 2.0 20v petrol sport 52reg i have owned this for about a year now and the fuel consumption is getting considerably worse. I used to get roughly 100 miles to £20 which is about 400 miles to a full tank which is £80 which i was quite happy with. Now i am lucky if i get 50 miles to £20 and 250 miles max to a full tank just wondering if anyone else had come across this or any one know how to fix this issue.
thanks in advance.

[caldirun]

You can't compare miles to quids, its dependant on fuel price and fuel has gone up, miles/litre or miles/gallon is the way to go!
If you get it perfect it will still be rubbish compared to a 1.9tdi, 54.6MPG from mine over the last 2 years!

[scotty33]

A good starting point, is the coolant temp sender, if it is misreading it may be keeping the car in cold enrichment mode? You could see with VCDS, look at coolant temp in measuring blocks.
Another possibility is lambda sensor, not sure which type passats use, but it is usually possible to test with a multimeter. go to Just Lambda, Suppliers of Bosch and NTK lambda sensors including zirconia and titania sensors by post
I'm guessing it will have a air mass meter or 'MAF' sensor after the airbox, this could also be at fault.

A fault code read may throw up something useful, but does not always tell you exactly what to change.

[Toonmania]

Good shout on the post above,
I 2nd the coolant temp sensor they are reknown for poor fuel consumption, failing that I would start looking at the MAF

[smithy602179]

i had this prob last year on my 2.0 l auto about 6 months after a timing belt change and after changing pretty much everything it turned out to be 4 rocker cover bolts were loose , whether the mechanic left them loose or if they vibrated loose i have no idea but after tightening them up it ran perfect for an hour till i hit an audi up the rear in an insurance scam (not my ins ) and wrote it off.
i replaced the following
2 lambda's
1 cat
air mass meter
plugs
leads
various pipes
coil pack
secondary air motor
coolant sensor
thermostat

if you do a search on my name you'll see loads of posts for fuel consumption

[Sam]

Before you start replacing things get the car scanned for any faults that may be present. That way you wont throw away any money that would be better spent on fuel

[smithy602179]

i scanned mine everytime the management light came on and everytime it was different , sometimes it went from being lean to being to rich and back in a day ?????? all cos of loose bolts .but totally agree with sam and get it scanned