2000 Ford Focus Increasing Fuel Consumption

SCOOBYDOO99999

MEMBER
2000 FORD FOCUS
4 CYL
FWD
MANUAL
117,000 MILES

Hi.

I bought an X-reg Ford Focus 1.8TDi in October 2009. The guy advertised it as 50+ mpg. However, the first tank only yielded 42mpg. I thought this may be due to the onset of winter, as every other car I've owned had higher fuel consumption during the colder months, and that mpg would increase during spring and summer. However, since October my mpg has gradually dropped to 37.

I have been to various garages and even had a diagnostic test done and everything has come back fine. The car has just been MOT'd and the emissions were fine. There is no visible smoke of any colour from the exhaust. The car has done 117000 miles and I had a new cambelt fitted a week after I bought the car. There are no oil or water leaks.

Over the past couple of months, I have replaced the air filter, had an oil & filter change, replaced the glow plugs, and replaced all the breather hoses. There is also no obvious sign that the clutch is slipping.

One garage even suggested that it may be a problem with the engine management system.

I am at a loss to understand why my fuel consumption is increasing. Could it be a problem with the engine management system, the fuel pump, the turbo etc. Any ideas?

Andy

1 Reply

DAVE H

MECHANIC
13,383 POSTS

Hello .. thanks for the donation, much appreciated.

There are a lot of factors to determine when calculating fuel consumption .. not every tank will average the same mileage .. weather conditions (hot/cold) and driving conditions (highway/motorway or stop an go) will all factor in the fuel consumption . a drop of 5 MPG is not a drastic drop and could be due to the factors mentioned above and not a fault on the car at all ...

you could try cleaning the throttle body and replacing the air filter again !

Most vehicles have ignition systems and a throttle bore. The vehicle's ignition system is the component that ignites the fuel air mixture inside the combustion chamber. When an ignition system fails, it can cause various symptoms such as stalling, rough engine under power, service engine light (check engine) and complete engine shut down. Be sure to keep your vehicle's engine and fuel system clean to assure the proper operation of your vehicle. Most vehicles today need a tune up every 35,000 to 65,000 miles depending on driving conditions.

Throttle Body
Most vehicles have an air intake system that will become clogged with air contaminants that the air filter cannot keep out of the system. This condition is called "coking" and can cause stalling as well as variable idle condition and poor mileage. Usually the throttle bore and plate are coated with a dark light tar that needs to be cleaned with every tune up.

Hope this helps