Sudden drop in MPG?

[liam]

For the last two months i've been getting maximum of 24.4mpg. I do a lot of town driving and on the way to work i rarely exceed 40mph. Round September time i was getting about 29/30 and at one point (i think the car had a funny moment) it went up to 39mpg really quickly with no change to how i was driving. It's had the Diverter valve replaced in the last 6 months so i can't imagine it is that again, could it be running rich? what would cause that? or are there any other theories you guys might have? I'm driving to Cornwall from Oxfordshire in a few weeks and 24mpg for a 200 mile drive will be a killer.

[GrayMK5GTI]

It's the cold winter air. It's affecting everyone's cars.

You should get mid-high 30s on a long motorway run, if you take it steady 

[Beej]

I do constant town to work and back, and I think the best I've seen is 26 mpg (end November) but over the last few weeks it's more like 24 ish

[dansmith180]

Is there any chance you've got a caliper sticking? Even if its only sticking a bit it can cause a big MPG decrease.

Look out for 1 wheel being particularly dirty and might be really hot after decent length journeys as well.

Otherwise as above probably just the weather.

[Saintsteve]

It's the cold winter air. It's affecting everyone's cars.

You should get mid-high 30s on a long motorway run, if you take it steady 

This 

[Beej]

Is there any chance you've got a caliper sticking? Even if its only sticking a bit it can cause a big MPG decrease.

Look out for 1 wheel being particularly dirty and might be really hot after decent length journeys as well.

Otherwise as above probably just the weather.

My car was in for a service last week and all reports were good , so mine appear to be ok.....

[wesrev87]

I think it is just the winter. I was getting mid to high 30s up to August/September and am now lucky if I get 33 mpg 

[Dave(tm)]

I think it is just the winter. I was getting mid to high 30s up to August/September and am now lucky if I get 33 mpg 

Yeah I'm hoping for this too...but it's been cold since I got the car, so let's see!

Dave

[liam]

Is there any chance you've got a caliper sticking? Even if its only sticking a bit it can cause a big MPG decrease.

Look out for 1 wheel being particularly dirty and might be really hot after decent length journeys as well.

Otherwise as above probably just the weather.

I'll check it out cheers!