Why is my gas mileage shooting the tubes??

[95EXP4.0]

I notice this recently since the weather has been turning colder. The only thing that I can think of is the grade of engine oil I use. Back when I used to get 270 on my trip meter with my 95 exp with an 18 gallon tank during the summer when I was milking it to the bare bottom and that's when I used 5W-30 oil. Later during the summer I switched over to regular quaker state 10-30 and now I am using the 10W-30 synthetic blend "for hard working vehicles (4x4)". I live in Chicago and the weather has been around the 40's lately. Do you think there might be too much resistance that it's making that big of a difference with my fuel economy? Should I most likely switch back to 5W-30?

 

[jimmiecakes]

It's hard to go on the info you've given..... If your gas mileage has taken a real noticeable hit, I'd look beyond motor oil as a cause. Some of the oil producers claims to "gas mileage improvements" are a little energetic.

5W30 is the recommended oil for the 4.0 but I can't see a switch to 10W30 having any dramatic effects to gas mileage.

 

[mrboyle]

Its because its cold! Your engine isn't warming up as fast therefore it is using more fuel.

 

[aldive]

Was the 5 W 30 you ran synthetic? The synthetic blend has such a small amount of synthetic in it its hardly worth it.

I would use 5 W 30 synthetic.

Good luck....

 

[Mike 92 XLT]

Another reason gas mileage drops in the winter is because cities start to use the oxygenated winter gas.

peace

Mike