Can a flaky alternator cause a drop in mileage?
I buy my gas primarily at the shell station a block away from my house.
I've always tracked my mileage. All summer I've been getting high 17's to mid 18's for mileage. Occasionally in the mid 19's with a lot of highway driving. Through mid November I was still getting lo to mid 17's.
Filled up on 11/12 with 17.6mpg for the previous tank
Oil change on 11/13
11/18 Fill up 16.6mpg
11/26 fill up 16.8mpg
12/3 fill up mpg to be determined on next fill up.
I will need to fill up either tomorrow or Saturday.
I'm almost on E and I'm only at 275mi for the tank. I should be over 300.
It's been below freezing, here in Chicagoland, for the last week. The alternator is squealing in the morning and my volt gauge looks a little low. I've also needed to jump it to get it started every morning this past week. The battery is an Optima red top no more than 3 years old. The alternator was replaced this past spring during my restoration project.
I'm thinking I have a flaky alternator. I'm just not sure if it will cause my mileage problems as well. My mileage hasn't been this bad since the fuel return line was obstructed a few years back. It got down to the low 14's then. I haven't checked the fuel pressure yet.
Also worth noting, This is the first winter with a K&N cold air intake on it. I don't know what to expect, regarding mileage, in the cold weather.