As title really, recently been serviced but only managing poor mpg. 1st thought was some kind of sensor or lambda?

Any tips for us mk4 owners to check?

Ta :-)

Edited 29 January, 201016 yr by mugly

Bin the polo and use your Golf Gti? :p

lol, not useful mate

haha couldn't help it, mk1 GTIs are so cool. What kind of MPG are you getting roughly? My 1.0 has a newly fitted low mileage engine but only does about 30mpg, which doesn't seem great considering I don't really rag it at all. I'd be interested to see if anyone can answer! I think lambda sensor could be a good shout

i'm having a similar problem mate.. caused by rich fuelling so i'm getting high CO and failing MOT emissions

with 6Ns its usually the coolant temps sensor. when this goes, the ECU keeps thinking the engine is cold and so keeps fuelling it richly. this part costs about £13 and is near your thermostat. unplug it and see what the engine does, or whack a multimeter on it.

failing that, it could be the oxygen sensor, which is either in your exhaust manifold or downpipe underneath the engine.. but these are expensive to replace.

oh, first call would be to check your air filter aswell.. if thats clogged up you will run really rich aswell. when did you last have a spark plug change?

i have just done 90 miles to £20 of petrol at the begining of the week, yesterday i did abit of a service, airfilter (had it a year and have never got round to it) pollen filter (was disgusting lol helps the heating system doesnt really aid fueling much), spark plugs pluged a few tiny hole in the exhaust with gungum, not it pull really well like when i just got it and everything seems ok for now!!!

temp sensors do go quite abit! do not replace unless you can catch the coolant in a bucket, or have aload of g12 to replace it! also dont do it when the engines hot it will scold you senseless

i have just done 90 miles to £20 of petrol

Ouch! My 1.4 is pretty good to be fair, can usually round it up to about 100 miles for every £10 you put in (40mpg?)

But that's motorway driving, on an economy run

Wow, that's good! I'd say that's nearer 50mpg... I do roughly 300 miles on a tank, which is about £45 I find. But that is mainly lanes and dual carriage way (not very fun when it's only geared for about 100mph in top!)

Had plugs and filter a couple of months ago, never used to be this bad. Think it's doing about 60 miles to a tenner steady driving.

I take it the temp sensor is the same as the 1.4?

yea mines the same,

I'm putting 40 ltrs in and getting 290 300 if I'm lucky used to do nearly 400. any ideas I've have throttle and temp sensor done?

yea mines the same,

I'm putting 40 ltrs in and getting 290 300 if I'm lucky used to do nearly 400. any ideas I've have throttle and temp sensor done?

pretty old thread revived here mate!

possibly lambda sensor, or maybe something to do with fuel system, like fucked pressure regulator

try getting vagcom on it and see if its throwing any codes.

or pull your plugs and check to see if it is actually running richer than it should (will be black, sooty).

it might just be your driving, around town for a 1.0 that doesnt seem too bad. on motorways it will depend what speed you drive at etc

the cold weather will cause poor fuel consumption also using the heater when the engine is cold will make the engine heat up slower.

But that is mainly lanes and dual carriage way (not very fun when it's only geared for about 100mph in top!)

mine does 100 in forth

the cold weather will cause poor fuel consumption

Could you explain that one to me mate

the cold weather will cause poor fuel consumption

Could you explain that one to me mate

loads of factors increase fuel consumption in cold weather:

- taking much longer to warm up, cold engine needs a richer mixture

- having more electric things on (heated window, heater blower, lights etc..etc...) the power to charge the battery comes from the fuel don't forget!

- colder air is denser so you are actually getting more oxygen molecules for the same volume of air. This means you burn more fuel to maintain a good air-fuel ratio. The result of this is your engine makes more power which is why cars often feel faster in cold, dry temperatures, because they are!

They all add up to a noticeable difference although it shouldn't be as much as going from 400 miles per tank to 300! Something is wrong there.