Been trying to figure out what to do about the mileage in my 2007 Mazda 3 2.3L hatchback. It has ~180000KM on it and has been a bit of a dog running at about 400KM per Fill up if I am lucky. on a bad fill up cycle i may get 320 KM or worse.... This has been a problem for about 18-24 months now with varying results. likely around 60/40 City/Highway ratio. Not a super aggressive driver but live at the top of the cut in North Vancouver, BC and do have to go down that hill a few times a week.
The only mod that I am aware of is K&N Cold air intake (was installed when i got the car used in 2012). Here is what I have done so far:
-MAF sensor wiring: i noted that the MAF wires were getting burned out at the connector and essentially broke on one of the 5 cables. I replaced the connector but did only a crimp job on the existing cable to the new cable/connector. probably about 2 years ago now. used to get tons of engine lights before this change.
-Purge Control Valve : replaced 2 years back.
-Washed out the K&N CAI filter and re-oiled as it was not replaced/cleaned for a long time (don't ask). Probably about 5 months ago when i did it.
-Spark plugs changed out 4 weeks ago.
-Replaced the K&N CAI drycharger bag as it has a large hole in it. 3 weeks new.
-converted the CAI to a short ram due to poor winter weather and to minimize the change of rain.
-MAF sensor replaced 3 weeks back as well.
-ran through a bottle of redline just in case.
-used to have some 225/50/18 rims but swapped to stock 16" winter rims with brand new Michelin cross climate 2's. (2 months old)
-engine light has come on /off periodically at different times but since the wash of the air filter, it seems to have gone away for the most part. When i do get one , it seems to go away after a few days on its own. I did not reset using the on/off method.
I have ordered a brand new CAI Filter as well as i am not sure if the original has buggered out, or cleaned it improperly/oiled it improperly. also ordered a new gas cap as another step.
What do you think? what else can i do here? not sure what else i can try here....