low mpg

[cosra1.4]

i recently bought a r reg 1.4 16 valve gls corsa.56k. recently mpg has dropped, driving style not changed,but tick over sometimes abt high at 1200. any suggestions?

[ianess]

Possibly a lambda? sensor on the way out causing a change in the fuel/air mixture. That may also be the reason for the increase in revs.
Easily checked out and fixed by a competent mechanic.

[cosra1.4]

where is this lambda valve located

[ianess]

http://www.howstuffworks.com/question257.htm

Usually near the top end of the exhaust pipe. If it's faulty you will get symptoms similar to the old-fashioned choke being partly on.....high revs and rich mixture = poor performance and excessive fuel use.
Hope this helps.