P38A 4.0-4.6 MPG!!

Yes i know, ya don't buy a 4.6 expecting 50mpg but my 125k vogue is doing 14.7 according to the trip cumspewter.

She's a late 2001 4.6 with the bosch injection.

she does have a wonky Lambda sensor does this affect fuel economy?

I would be ok with 18-22 mpg but 14 seems silly am i right???

Yep, sounds poor but it depends what you're doing. On German autobahns at 80mph I get around 21-22mpg but on the Czech country roads I get around 15mpg.
When I'm in the UK using it I get around 18mpg average (busier motorways requiring more acceleration etc)
That's real mpg. The computer in my experience is about 1-2mpg over what you really get.

usually 24mi journeys mostly open roads 50-60mph

sometimes she is taken up the M way to blow er out.

Have you done a 'real mpg' test ie full tank to full tank?
Our non-LR petrol auto achieves just over 10% better than the computer read-out.

My Mercedes truck averages 11.5 mpg over the month and it weighs a minimum of 16 tonnes and up to 44t

I know it's a different beast but my D2 4L V8 used to get 14 ish on short/around town journeys. On a good month it was around 18 . Long journeys were around 21-23.

I have done a brim to brim lol

15mpg was what i got lol

can't do it too many times at £110 a hit!!!!

anything more than 15mpg on these,is a bonus,imo.

My 4.6 Vogue does an indicated (Trip Computer) 22MPG on long runs.

funrover said:

I have done a brim to brim lol

15mpg was what i got lol

can't do it too many times at £110 a hit!!!!

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Mpg is highly variable on how and where you drive. 15’ish mpg +- is not exactly unexpected in such a Vehcile.

For general normal driving, ie not for economy or speed. On average U.K. roads not in peak periods, not high speed runs nor city only driving. The. I’d expect 16-18mpg average.

Lower mpg can be caused by many different things though. Fuelling. Sticking brakes. Sticking aircon clutch. Tyre type.

@funrover I known it seems a big difference but 14.7 compared to 18 is approx 50- 60 miles on a full tank. Considering we all knew they were gas guzzlers on buying, an extra 50 - 60 miles per tank doesn't seem enough to worry about. Unless, of course, you are filling the tank every week or every couple of days.

If I get over 16 in the 4.6 I am a happy bunny....oh and mines on gas so that is the equiv. of around the mid 20's - 24 to 26 something like that.

Saint.V8 said:

If I get over 16 in the 4.6 I am a happy bunny....oh and mines on gas so that is the equiv. of around the mid 20's - 24 to 26 something like that.

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I have LPG a sequential BRC system.

79p a litre around my neck of the woods

funrover said:

I have LPG a sequential BRC system.

79p a litre around my neck of the woods

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blimey - 54.9 at the Shell garage round the corner from work!

I get 20-21 on a run. But I find the warm up cycle is a killer on these. I'm guessing about 10 mpg while everything is warming up. Mine is a gems though and the speedo reads exactly the right speed instead of to high by a few mph. I think it may be my l322 18inch wheels. Around town with cold start yours sounds fine at 14. On a run to low. Could be many things tbh but lambda is vital to correct fueling. As is no air leaks in the intake/pre lambda exhaust. Maf is also critical. It's expensive to change the plugs on a Thor though they do last if they are the correct ones. So this can be neglected. Cam wear can lead to poor economy due to inefficiency.
Jb

1977 RRC, 3.5 low compression V8, carburetor model, 4 speed manual, a whole 13MPG on highway work, owned it for 11years, '86 to '97, loved it, it'd go past everything except a petrol station, but couldn't afford to run it at today's fuel prices.

Gazbo said:

1977 RRC, 3.5 low compression V8, carburetor model, 4 speed manual, a whole 13MPG on highway work, owned it for 11years, '86 to '97, loved it, it'd go past everything except a petrol station, but couldn't afford to run it at today's fuel prices.

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Same here lol

i had a 1974 3.5 that did 7mpg around town and 10mpg motorway.

my 1983 3spd auto 3.5 did 3mpg towing a trailer!!

nowadays at 1.20 a litre its impossible!!

Saint.V8 said:

blimey - 54.9 at the Shell garage round the corner from work!

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The price of LPG around me is stupidly expensive 79p a litre is only a small saving compared to 1.14 a litre petrol.

still a nice car to drive though!!

funrover said:

i had a 1974 3.5 that did 7mpg around town and 10mpg motorway. my 1983 3spd auto 3.5 did 3mpg towing a trailer!! nowadays at 1.20 a litre its impossible!!

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No offence but those figures are scarcely believable !
Back in the 'nineties I owned WW2 American army trucks (Dodge & Chevrolet) with short gearing & low comp. petrol engines that weighed more than a RR & still returned 12 mpg on a run.
Your lowest figure could be achieved with a 6x6 Diamond T with a eight litre side valve petrol engine from the same period.

norseman said:

No offence but those figures are scarcely believable !
Back in the 'nineties I owned WW2 American army trucks (Dodge & Chevrolet) with short gearing & low comp. petrol engines that weighed more than a RR & still returned 12 mpg on a run.
Your lowest figure could be achieved with a 6x6 Diamond T with a eight litre side valve petrol engine from the same period.

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I don't believe them either.