Fuel consumption suddenly getting worse

[Tvr_Edd]

Right, here is a little background to my car.

Car made 405bhp at Jools on MBE, it is 4.5 RR. The car has got the later milder cams and joo had to lean out a lot of fuel to get the power he did. Obviously the cars not running lean, but he found by taking fuel out of the map he got more power.

The car then went to be serviced where I was told the car was down on power.

The car then suffered oil pressure problems which was identified as oil return pipe blocked with silicone and all fixed.

Car seems to idle very roughly, has a bit of a missfire at 2-3k which it easily gets through but is noticeable.

Someone else who is familiar with cerberas says it is missing torque in the midrange and top end.

The car will go back to Jools to be looked at and try to identify issue but i noticed the other day, over a whole tank my mpg was 15mpg.

This isn't uncommon but my car regularly (with spirited drives) returns 20-28mpg with 20 being the bare minimum even after spirited runs.

What could be wrong to cause the excess fuel consumption and possibly the slight bad running?
Haven't got access to diagnostic which I know is the simple answer but wondered if I could look at the car myself before getting it to Joo

thanks

[SimonSparrow]

Joo will figure it out, but you could check for a blocked air filter or dragging brakes. Other than that, might as well wait until diagnostics can be done.

[Tvr_Edd]

Thanks,i'll check the air filter later on

[Extra 300 Driver]

Was it as a result of the service?

Its just I am thinking that if the service guys reset everytihing to standard, having seen some odd readings after Joolz worked his magic, then they may have reset everyting back to normal.

[Tvr_Edd]

could well possibly be but i was assured the chip/map wasn'touched

[Mars]

I never get anything like the economy you quote Edd. I reckon 15mpg is about my norm. The amount of fuel you use is proportional to the amount of power you use. If your engine can make more power, and you use it, you'll use more fuel.

The best way to determine the issue it to get it to Joolz for a check-up as per his invitation. Then get an Emerald.

[Work-Shy-Wanabe]

Lambda bust?

[Olly]

Mars said:

I reckon 15mpg is about my norm.

We typically get about 19mpg with "normal" Cerbera driving.

16mpg is fairly normal among other Cerbs, with mid 20's being possible if your sensible on the motorway.

A flat spot sounds like something isn't right though. If you don't mind getting your hands dirty, there are all sorts of things we can get you to check, but it is awkward without the laptop/software....