I noticed that my V6 was consuming more fuel than usual, actually ALOT more fuel.

I was previously getting 600-650Km per tank (western highway cycle) and in the past 3-4 weeks I have been struggling to get to 500Km per tank.

I dont buy fuel at any particular outlet, but usually try to get BP ultimate (98oct)
I always fill with either 98oct or premium if thats the highest grade available.


As soon as I noticed the consumption drop, I serviced the car again, it was only 3600 since its previous service (oil + filter change, air filter check, plug check) but I decided to do the following:
oil (magnatec),
oil filter,
air filter,
fuel filter can,
new factory leads,
new bosch super 4 plugs,
added a bottle of STP injector cleaner to the tank,
adjusted the timing as per the mitsu dealer workshop manual,
and even checked the tyre pressures (I run 36 and 38PSI).

Everything was identical brands to the previously used as I buy in bulk.



I checked for binding brakes, bearings etc etc, havent altered my driving style, I previously (and still do) drive with the aircon on full for the whole trip, and I only ever have the trans control button in POWER.

The day temperatures have started to drop from 42-44c to more comfortable 35-38c.

I even took it to my local mitsu outlet and had my friend plug it up and check the codes, none were found.

Is there anyone with any ideas as to what to look for?

Hello gapsa Mcgee,

At any time did you disconnect your battery? If so, the ECU is going through a re-learn process and fuel consumption will suck!

TG