Emissions Light - shocking mpg, linked???

[LenasClio]

So my emissions light has come on, shortly after my avg mpg has plummeted down to about 23 mpg!! Havent had the car long and im no mechanic so dont really know what to look for!! any ideas anyone????

 

[columbo]

Lamda sensor(s) would be my first port of call. Might be worth changing thermostat and CTS if your needle isn't going to the halfway mark.

Both these can cause poor MPG.

 

[LenasClio]

Is it going to cause damage (apart from to my wallet) if I dont get it seen to just yet??

 

[columbo]

No, obviously don't leave it for ages or it could lead to other problems, but you'll be fine for a short while yet.

 

[LenasClio]

nice one, cheers for you help mate!