Gas Mileage- Winter

[moe19x]

I have a 98 328i and i dont drive it too hard. In the summer between highway and city i averaged 400 miles a tank. For the last 2 tanks of gas ive been getting about 200miles a tank only. this is just city driving! is that normal?? or do i need to lookin to a probelm or something? i did have a recent oil change and my bro picked up the wrong oil, he picked up some shitty brand of oil but it was syn 5w30. should i change that? or leave it till the next oil change in 2500miles? by the way i am in ontario canada the temp has been around -20C for the last few weeks
thanks

[drz]

City driving is less efficient than highway driving. SInce you have been doing only city driving recently, it explains a drop in gas mileage. Also, in the cold weather, it takes the car longer to reach operating temperature, before which the engine management system tends to run rich, thus using more fuel.

However, is your check engine light illuminated?

[PhatCat]

Originally Posted by drz

Also, in the cold weather, it takes the car longer to reach operating temperature, before which the engine management system tends to run rich, thus using more fuel.

Not to mention that in the winter in Ontario, you'll be running your car cold much longer and more often while you are sipping your morning cup 'o java and before you leave work...that accounts for more than you think.

[moe19x]

Originally Posted by drz

However, is your check engine light illuminated?

No check engine light on, but just recently before the cold began i had my rad, fan, fan clutch, and waterpump changed. I was worried maybe that had to do something with it, just in case it wasnt installed right.

[drz]

Originally Posted by PhatCat

Not to mention that in the winter in Ontario, you'll be running your car cold much longer and more often while you are sipping your morning cup 'o java and before you leave work...that accounts for more than you think.

tru

[moe19x]

On my last tank of gas i only got 185 miles which is like 13 mpg which really worries me. any idea?? it runs rough when i turn the car on for a few seconds and then its normal again. Also recently after i had my coolant replaced2 weeks ago ive had to add coolant a couple times (like 3 times a cup each time) is that normal? i cant see it leaking anywhere also the system has pressure so i dont think there are any leaks. any idea/?? specaily about the gas mileage? my 98 f150 gets better mpg at the moment

[94BMW325i]

my car has ran a little rough at first when it is cold. around 24 degrees fahrenheit or so. I think it is just the cold, and your car is running rich.

[drz]

When where your spark plugs and ignition coils last changed?

[moe19x]

Originally Posted by drz

When where your spark plugs and ignition coils last changed?

spark plugs were changed about a year and half ago

[moe19x]

could it be the O2 sensor?

[atanakin]

just like ive told so many people before you, take it to the dealership and have them diagnose it for less thann 100 dollars. save yourself this hastle.