my son's x type (04 3.0ltr) gas mileage dropped recently from 21 to 17. He has always used regular not premium. will premium get him any better mpg? it has 80k on it should I change plugs? any thing else? thanks bob

 

mphy, I would start with new plugs and see how things go from there. Also keep in mind that I have noticed my car is very subjective to outside temperature and it will have a dramatic effect on the mileage. So, also keep that in mind. 17 is a little low, but i have seen my car drop down near that range. Part of it depends on how much warm up is done.

If you need more help, let me know.

 

Sorry - posted reply to wrong thread somehow!

 

mphy 98, I was consistently getting below 20mpg and I thought it was normal. Since that time, I have changed my plugs, plenum gaskets, PCV valve and hose, sealed my brake booster, and installed new IMT o-rings. Since I have replaced all of that, my mileage went from about 18mpg to 21mpg in the city and increased another 2mpg on the highway. I have also heard of many cars getting bad mpg because their upstream o2 sensor has gone bad but hasn't tripped the check engine light. I know that this is the fact for many subarus and imports, yet I don't think anyone has reported before and after mpg from doing this on an xtype.

 

Mphy, over the last 15,451 miles my car has averaged 18.4mpg. The best was 27.8 and the worst 15.0. The vast majority of my driving is stop/start traffic.

I run the car exclusively on 98RON fuel here in Australia, which I understand is the equivalent of 94AKI fuel in the US and Canada.

Given the information in this thread, sounds like I need to do some minor engine overhauling!

Regards

Rob

 

Rob,
Also sounds like you need to go to 95RON fuel too ...... 98RON is such a waste and has no benefits.

 

Larry, the challenge is the local (and convenient BP) servo has either 98 or that damn 91 with the ethanol.

Since I've had the X-Type I've filled up 76 times, 66 times with BP Ultimate 98, 7 times with Caltex 98 Vortex, twice with Shell V Power 98, and only once with Catlex 95 Vortex. I've had a great and consistent experience of the BP Ult 98 in other cars and various motorcycles.

Given my love of spreadsheets , I might try a trial in the new year with Caltex 95 in the X-Type, perhaps half a dozen fills and report back on the experience.

Rgds

Rob

 

Wow, you're the man! That reminds me of my parents tracking gas prices and calculating fuel economy on a pad of paper in the glovebox when I was a kid.

 

Rob,
I assume you are familiar with Motormouth.com.au a great online tool to search your locale (by postcode) for any specific fuel you may require...

Anyways, heres that url;

MotorMouth - Fuel Prices and Petrol Prices Australia

 

If it makes you feel any better the best I got has been 15 MPG I figure it's because work is only 7 miles away thru the city.

 

Right, so as threatened, here is the update on using Australian 95 RON versus 98 RON...

Since switching to 95 RON on 16 December I've driven 2,524 km in my usual pattern (80% stop start city, 20% freeway).

I've filled up with 316 litres, at a cost of $A494.92, averaging $A1.567 per litre. All fuel has been bought from the same outlet (Caltex in Five Dock, Sydney).

Economy is 12.51 litres/100km, or 22.58 MPG (imperial) and 18.80 MPG (US). This compares with 12.65 litres/100km for 98 RON (22.33 and 18.59 respectively). Pump price difference is between 4 and 5 cents (95 cheaper than 98)

Essentially there is no discernible change in driving experience between 95 and 98, fuel economy is near as the same, and I'm (as of the pump price this morning) saving about A$2 per fill up.

So, 95 RON all the way from here...

Regards

Rob