Hi, with fuel going up about 30% I am looking for ways to improve my fuel economy.
Or if there is some thing wrong with the vehicle.
I am getting about 13.8 mpg as I drive around my area, local roads and highways.
BMW M62
I see one of our members is getting 17.6 mpg local and 28 mpg on the highway.
Any ideas what I can do, or what I should check, or what could be wrong, if any thing. RR 2005 4.4 petrol
Any spelling mistakes are the fault of spellchecker
Previous MG J2, CITROEN light 15 x 2 gone unfortunately
Present MERC 180e, RANGE ROVER L322, JAGUAR XJS, MERC 280SE, MG F, JAGUAR S-Type 6v 2003, jaguar s-type 8v 2004, Ford Cougar

would larger tires help with the fuel mpg RR 2005 4.4 petrol
Any spelling mistakes are the fault of spellchecker
Previous MG J2, CITROEN light 15 x 2 gone unfortunately
Present MERC 180e, RANGE ROVER L322, JAGUAR XJS, MERC 280SE, MG F, JAGUAR S-Type 6v 2003, jaguar s-type 8v 2004, Ford Cougar

Run your tyres at the highest safe pressure to reduce rolling resistance . A larger wheel circumference ( bigger tyres) will effectively mean taller gearing but depending on where the torque band is in the engine it may or may not result in better MPG. Biggest difference will come from how you drive i.e lower you speed on the highway and accelerate as slowly as possible to get up to speed. Also drive with maximum anticipation of the road ahead to avoid using brakes + accelerator ( brakes turn momentum into wasted heat which needs replenishing with burning fuel). 2012 TDV8 Vogue (L322)

thanks for your comments
i do drive as you say but i often wonder if i should if i should floor it some times, just to clear the system
taking a jaguar and opening it up was part of the method of fixing some engine problems when i was younger RR 2005 4.4 petrol
Any spelling mistakes are the fault of spellchecker
Previous MG J2, CITROEN light 15 x 2 gone unfortunately
Present MERC 180e, RANGE ROVER L322, JAGUAR XJS, MERC 280SE, MG F, JAGUAR S-Type 6v 2003, jaguar s-type 8v 2004, Ford Cougar

It’s always worth checking the brake callipers aren’t seized, the rears are particularly prone to doing it without any obvious symptoms.

thats a thought
thanks RR 2005 4.4 petrol
Any spelling mistakes are the fault of spellchecker
Previous MG J2, CITROEN light 15 x 2 gone unfortunately
Present MERC 180e, RANGE ROVER L322, JAGUAR XJS, MERC 280SE, MG F, JAGUAR S-Type 6v 2003, jaguar s-type 8v 2004, Ford Cougar

Assuming everything is mechanically is correct, then the big impact is driving style. Easy smooth driving does it every time.

trew RR 2005 4.4 petrol
Any spelling mistakes are the fault of spellchecker
Previous MG J2, CITROEN light 15 x 2 gone unfortunately
Present MERC 180e, RANGE ROVER L322, JAGUAR XJS, MERC 280SE, MG F, JAGUAR S-Type 6v 2003, jaguar s-type 8v 2004, Ford Cougar

M62 is one of the best ever candidates for an lpg conversion - I had two in BMWs and one in my l322 ran great Current stable:
2006 BMW M6
2007 4.2 V8 S/C FF
Gone:
2002 4.4 V8 FF

Thinking about tires, my RR is fitted with 275/45R20, which is smaller in diameter than the original 255/55R20,
255/55R20 are not a popular tire and are very expensive hear in Australia, so I am told, where as the 275/45R20 is quite common.
I had some 275/60R20 offered to me at what I thought was a very good price, so I bought them.
Now I go to read the posts on the forum and find they are too big.
They have an increase in radius of 0.795” against the 255/55R20 which I thought would be no big deal and they wont fit in the spare wheel well, which I knew
Tire sizes dia tire width rev/p/mile
255/55r20 31.4” 10.04” 649.68
275/45r20 29.74 10.83 678.05
275/55r20 31.91 10.83 632.04
275/60r20 32.99 10.83 611.00 RR 2005 4.4 petrol
Any spelling mistakes are the fault of spellchecker
Previous MG J2, CITROEN light 15 x 2 gone unfortunately
Present MERC 180e, RANGE ROVER L322, JAGUAR XJS, MERC 280SE, MG F, JAGUAR S-Type 6v 2003, jaguar s-type 8v 2004, Ford Cougar

Does your car have an EGR system?
I’m not sure at what year they were mandatory, especially in your part of the world…

I once did a google search about EGRs and now my google feed keeps suggesting websites about them for me to read. There are many click bait articles, but all seem to put reduced performance and fuel economy at the top of the problems list.

LPG, driving styles, tyre circumference, etc are all good suggestions too, and a combination of those may bring you some of the saving you are looking for.

In line with my egr suggestion, ensuring the engine is running as well as possible may help.

HTH Currently driving: 2012 L322 SE Overfinch 4.4 tdv8

Past rides:
2014 Audi Q7 3.0d (good riddance)
2010 L322 Autobiography 5.0 Supercharged
2011 L320 HSE 3.0 sdv6
2014 Jaguar XF-RS 5.0 supercharged
2007 BMW 535D
2005 Mini Cooper S

https://www.fullfatrr.com/forum/topic59478.html

Also, if your tyres are incorrectly sized, then ignore the on board mpg readings.

If you want to know your true mpg, the record your miles and gallons used when at the pump.

And just a thought, is your mpg display set to US gallons? I forget the terms used in my car, but feel it’s US and UK mpg… Currently driving: 2012 L322 SE Overfinch 4.4 tdv8

Past rides:
2014 Audi Q7 3.0d (good riddance)
2010 L322 Autobiography 5.0 Supercharged
2011 L320 HSE 3.0 sdv6
2014 Jaguar XF-RS 5.0 supercharged
2007 BMW 535D
2005 Mini Cooper S

https://www.fullfatrr.com/forum/topic59478.html

yes thats a thought, thanks RR 2005 4.4 petrol
Any spelling mistakes are the fault of spellchecker
Previous MG J2, CITROEN light 15 x 2 gone unfortunately
Present MERC 180e, RANGE ROVER L322, JAGUAR XJS, MERC 280SE, MG F, JAGUAR S-Type 6v 2003, jaguar s-type 8v 2004, Ford Cougar

Are you running on the 275 60`s? if so do they fit ok. I was lucky to pick up a set of 5 275 55 20 Bridgestone's at A$20 each brand new, I am still waiting for my current tyres to wear down to warrant changing them. Currently on 275 50 '20s. 2007 TDV8 VSE
2003 TD6 gone.
2002 P38a gone
1999 P38a gone
1997 p38a gone
1993 VSE gone
1992 VSE gone
1966 Series 2a with V8 conversion gone

No, I only picked them up to day
tire dia width R/Mile
275/55r20 31.91 10.83 632.04
275/50/20 30.83 10.83 654.24
The 275/55/20 has an increased radius of 0.54” hardly any thing, I would have thought.
$20, haha, my luck wasn’t that good, mine were second hand, about 70/75% I think
I paid $50 each
last week i bought a new tire, now if these fit, i wont need it, RR 2005 4.4 petrol
Any spelling mistakes are the fault of spellchecker
Previous MG J2, CITROEN light 15 x 2 gone unfortunately
Present MERC 180e, RANGE ROVER L322, JAGUAR XJS, MERC 280SE, MG F, JAGUAR S-Type 6v 2003, jaguar s-type 8v 2004, Ford Cougar