colder climate - colder plugs/lower temp stat

[navyblue2000]

I saw a consistent 24mpg this summer with mostly city driving. I noticed a combined 24 last winter. between winter and summer, i switched to copper plugs (same heat range, but coppers are colder than plats), and a 180* thermostat. my mpg was great during summer, i was seeing awesome mpg pure highway.
HOWEVER, i get about 18.5 mpg right now (40* weather) with mostly HIGHWAY driving.
My only thoughts are - lower motor temp + lower air intake charge temp + colder plugs = more air = more fuel = incomplete burn (cold) = bad mpg?
is that correct? I've been told that putting the plats back in for winter and the stock thermo will allow for more mpg. I'm not concerned with performance, as local tracks are close till the end of february.
has anyone else who actually lives in a place that gets COLD noticed a difference like this?

[Dominic]

It might be possible, it probably does run richer. Try just swapping thermos and see if that helps, then try just the plugs and see, tell us what happens [img]smile.gif[/img]

[Scott T]

You're not alone. I've noticed this change also. I always reset my trip odometer whenever I fill up. In the summer my mileage goes up also. I figured it had something to do with it running richer also. I thought that maybe the car stays in a closed loop longer until it warms up and then goes into open loop or visa versa. I noticed in the summer runs to Cincy. the mileage goes up.

[Arctc Wolf]

try upgrading the ignition to a msd-dis-4 and see if it get's ur mileage back, since at lower rpm's, there's less heat 2 help burn the mixture and the multiple sparks will help burn it all.

[Bass482]

Have you also taken into consideration the amount of time you let your car warm up to operating temp?

I've always thought that this was the reason I was getting worse fuel economy, although your idea makes me look at it in a different light. Good Luck! [img]smile.gif[/img]

[ December 20, 2002: Message edited by: Bass482 ]</p>

[Scott T]

My car sits in a garage and it still has worse gas mileage in the winter than in the summer. I have Accel 8 MM wires and AC rapid fire plugs.

[Jhonathan]

thats wierd, mine gets better gas milage in the winter?

[Jason]

<blockquote>quote:</font><hr>Originally posted by Jhonathan:
thats wierd, mine gets better gas milage in the winter?<hr></blockquote>

SO does mine. I think its because im more careful this time of year. I dont mash the gas a fraction as much as i do in the summer time.