Hi all. Just wondered if anyone else has a massive change in mpg now the cold weather is here. I know the engine has to work harder to get and keep warm but my mpg has dropped to about 18 mpg. Thankfully the petrol prices have dropped too but I wouldn't think cold would effect it quite as much.

Another thing I wonder is would incorrectly gapped spark plugs make a massive difference? I changed the spark plugs a few months ago and not sure if the gaps were the same as my previous ones. Would a slight difference in gap make mpg drop this bad? Thinking of getting some new ones fitted and buying from ford dealership. Others I bought were from an indy car parts shop. Hope someone has a clue for me

That's a huge change in mpg at most it's about 3-5 mpg well on a diesel petrol should still be about that, sounds as though it could be running very rich auto choke stoking maybe

Don't think the spark plug gap would have much of a difference on your mpg.

But at this time of year if you're having to sit with the engine running while the car warms up and heated screens do their job then obviously that reduces mpg.

Somehow mine seems to have got better by an mpg or two, I'm up to 27mpg now :P

Yeah my mpg is starting to drop i`ve noticed since the cold has come .

Forgot to mention it's a 1.8 petrol mk2.5. I've never had great mpg. Can get 35 to 40 on a run but around 24 round town which is my main driving. Plus live in Sheffield which is basically all hills so expect rubbish mpg round town lol. I don't leave engine running I just defrost window then go so it's a mystery. When you say running rich how would I know? I recently cleaned all my throttle body and it was caked in carbon. Would that be a sign?

Ah, the 1.8 mk2.5. My mpg in mine has always been crap, not sure what I am getting at the moment, next time I am out in it I will check and get back to you, see how different it is.

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Same here,the computer says 43.7 mpg,but on a 40 mile trip the fuel gauge says I've used nearly 3 gallons of diesel.

It will happen. The air is denser so more fuel is needed to get the mixture right. Also there is more load on the car what with lights, wipers, heating etc. being turned on.

On the plus side, the engine will be a bit more responsive. My 2.0TDCi has a bit more poke than normal.

Trouble is with mine.it's been like that for over a year now.hot or cold weather.so i'm going to take it to my local garage to have a diagnostic machine have a go at it,as I can't find anything wrong with it.

mines dropped ever so slightly

dropped between 2-5 MPG

due to more use of electrics

I too have a 1.8 petrol 2.5

Yep. Mines gone from 52 mpg to around 48mpg

1.6 duratorq diesel

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I reset my settings before I drove about 30 mls home on a mixture of main and back roads at night and ave about 43 mpg . 55plate focus zetec climate

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It will happen. The air is denser so more fuel is needed to get the mixture right. Also there is more load on the car what with lights, wipers, heating etc. being turned on.

On the plus side, the engine will be a bit more responsive. My 2.0TDCi has a bit more poke than normal.

Downside is the amount of grip available to actually make use of the extra poke

43mpg after resetting the trip isn't the average mpg that's the mpg for that trip

Downside is the amount of grip available to actually make use of the extra poke

Oh yes. I've got to be a bit more gentle with mine at the moment and make sure it is in a straight line first.

Your average fuel of around 24 mpg and now 18mpg in the cold weather is roughly the same as I get with my ST.

Thought you would get more than that with the 1.8

Your average fuel of around 24 mpg and now 18mpg in the cold weather is roughly the same as I get with my ST.

Thought you would get more than that with the 1.8

depends on the distance too

I do really short journeys to work in my 1.8 its currently says 27 mpg

Previous mk1 1.8 in winter was around 28-30 mpg

If its short journeys then it'll drop as the engine doesn't warm up or you're thermostat isn't working correctly causing it to over cool you're know as you're coolant temp would be at 60 if its short journeys and the heaters on full blast and lights etc it will drop clogged air filter won't help either.

I think it's definitely been the cold weather because as it has been a little but milder (can't say warmer) my Mpg has gone up to around 21 and is still climbing slowly. Bring back warmer weather