Poor mpg ?

[rollerdan]

Hi guys i dont know if you can help. Basically my 172 seems to be a bit sluggish and is using alot of fuel 25 miles to a quater of a tank . My exhaust is leaking from the cat and the back box but surley it wouldnt use that much fuel. Also its very hesitant when cold lots of flat spots through the rev range . Ive replaced the pre cat lambda . A few months ago isit possible for it to fail again ?

 

[Fletcher]

When was it last serviced?

 

[montana]

What does the in car mpg read ??

 

[sbridgey]

when was the cambelt changed?

 

[rollerdan]

Cambelt was changed about a month ago with dephaser also had an oil change .

 

[Tony Hunter]

Dare we ask who fitted the cambelt ?

 

[TimR26]

If the cat is leaking before the first lambda it will think its running lean and chuck more fuel in to compensate.

You should really fix the leaks regardless though.

 

[chris1984]

Is the eml on?? If so then id imagine its the pre-cat lambda, but still sort the leaking exhaust joints first though!

 

[rollerdan]

Renault did the cam belt .