Rapid increase in fuel consumption, 400miles per tank down to 300miles

[larry]

Hey,

Would really appreciate some advice on this as the cars suddenly developed a fault somewhere in the fuel system I'd presume whereby a full tank would normally last around 400miles which is the weekly commute, this has gone down to a little over 300miles per tank.

The only other sign of a fault is that there is a flat spot under hard acceleration, it does pick up afterwards.

Runs fine on tickover and doesn't stall. Changed the plugs and filters after the problem developed but no improvement. No warning lights on the dash either.

It is a V reg (2000) 1.4 16v Alize currently at 157,000miles which has been largely fault free over the last 80,000 miles.

Any help really appreciated... expensive having to fork out for extra fuel

Larry

 

[Ben]

Tyre pressures?

 

[Saner]

lamda sensor?

 

[Fred@BTM]

i'd say one of the pencil coils starting to break down IMO

 

[sideways danny]

Lambda i'd say

 

[larry]

Cheers for the replies, good stuff to go on.

Just had a search and it wouldn't be that expensive to replace either of those but is there a clear way of telling which might be faulty? Any visible signs if they were removed or a simple test that can be done... other than a proper diagnostics test.

Larry

 

[jack_kemp]

To test the lambda's, swap the pre and post cat sensors over.