Fuel Economy Decline

[smartypants]

I've recently noticed a significant drop in my fuel economy - I drive the same route to work nearly every day, and this morning I did my "frugal" run, where I can usually eek out 36-38mpg. However I really struggled to get it to 33mpg, despite a very light foot.

Recently changes to the car have been:

New tyres all round.
New cambelt
New waterpump

Could any of these factors have an adverse affect, or can I attribute this to a drop in air temperature, although that usually means better economy doesn't it?

Its not alarming, but its a significant drop for me to notice - which is annoying. Why do they put mpg displays on cars these days? I was better off being ignorant to the fact!!

[Rhyso]

Colder weather? 

I know it does affect diesels so not 100% sure the effect on petrols

Colder weather normally helps produce more power as the air is denser (Hope thats right).  More power = worse fuel economy

[Steve30]

I would be well happy with that Economy!! I get 20 around London on the Mway 32 , so I think your doing alright!!

[bacillus]

I have found that I get less mpg in the winter vs summer even on long distances.

[smartypants]

Colder weather? 

I know it does affect diesels so not 100% sure the effect on petrols

Colder weather normally helps produce more power as the air is denser (Hope thats right).  More power = worse fuel economy

True! Definitely cold affects diesels, and you could be right about the power/economy - I am not sure in that department... lots of factors affecting it, just put it out there for suggestions

[smartypants]

I would be well happy with that Economy!! I get 20 around London on the Mway 32 , so I think your doing alright!!

As I said I'm not alarmed, just a bit annoyed - and its been very consistent and predictable depending on my driving style until recently. Yes I should be happy with that return on such a car

[smartypants]

I have found that I get less mpg in the winter vs summer even on long distances.

Cheers, thats what I've put it down to... will keep an eye.

[FamilyDub]

Colder temperatures mean denser fuel, which helps filling up, so I'm led to believe.

Dunno about the actual use of fuel in colder temperatures though...  :embarassed:

I would be well happy with that Economy!! I get 20 around London on the Mway 32 , so I think your doing alright!!

Me too! 

[robern2]

Car always runs richer on start up in colder weather and takes longer to get to optimum operating temps.

[Synchronize]

I've recently noticed a significant drop in my fuel economy - I drive the same route to work nearly every day,

Ditto, mine has been like it since the drop in temps....