MPG gone down the pan

[bongi69]

I've noticed after the last few months that my 2002 1.2 is drinking petrol. After using fuelly to get the MPG, the average is 33 UK MPG. Looking at other users MPG's, mine seems way off from the average.

Now I did have it back in the dealers a few months back, and he did say that the O2 sensor is not working correctly, and he told me to come back a week later and he'd replace it. Long story short he had the car for a week, kept fobbing me off, so I just asked for the car back. Obviously no work was carried out on it.

Just wondering, would the O2 sensor giving false reading affect the MPG by that much?
And if one was to replace it, would you have to reset the error code to get the replacement one working correctly?

Edit: When I originally got the car, I would regularly get 350 - 400 miles from a full tank. Now I'm lucky with 250

 

[ScottHmk4]

yeh that will affect it, if its coming up as a fault on VAGcom, try clearing the code and rescan-ing it. if it comes back then it will defo need rplaced as just clearing a fault is not solving a broken sensor. My 1.2 is worse than that, im on a mission to fix mine but unfortunetely ive scaned mines over and over and nothing to indicate why mines drinking like a fish, least u have something to go on. so im gonna service mines, replace suel filter and clean out EGR valve and go from there, im getting like 100 miles to a half tank, used to get like 180 odds to £20, due to change to the dark side of derv

 

[Veyron]

I get about 120 on half a tank

 

[bongi69]

Well as I explained in another thread, my car is due in to the garage (a different garage, the main SEAT dealer in Dublin) to have the steering control rod replaced, thanks to the recent snow and a kerb. So will get them to have a look at it while its in

 

[ScottHmk4]

keep us up to date with what happens

 

[gezmeister]

I average 34 in my leon cupra

 

[CJRamze]

Its airflow, I imagine (Not 100%) if the sensors out it will be requesting too much fuel to burn the air that isnt even there. If I'm correct that this sensors outta whack and your raping fuel a sensors the last of your worrys.

I'd have the garage look at your spark plugs for early signs of damage / wear.

 

[ScottHmk4]

is there a way to adjust the airflow require through vagcom? see maybe when i removed the induction kit the demand for the higher air intake was still there, maybe?

 

[bongi69]

I've checked the air filter and ducting quite recently, and there's no obstructions.
I'll change the O2 sensor and if the MPG doesn't improve, I'll look further into the airflow, and airflow sensors

 

[Gooner_Mike]

It is chuffing cold at the moment... that can affect MPG too.

 

[bongi69]

It is chuffing cold at the moment... that can affect MPG too.

Well it is here. -4 at the moment. But I noticed the MPG being affected back in October, when it wasn't cold (well by Irish standards anyways). The MPG has dipped due to the cold snap by about 2MPG