I always check my MPG when I fill up. I was getting 18-20 but now I'm getting 15. My plugs and wires are about a year old and the cap and rotor are like a couple months old. I just cleaned the K&N air filter and changed the oil. The only thing I did different was but a bottle of Lucas fuel treatment in.

Any suggestions on what I should do next?

 

How many tanks have you been getting the lower numbers and has it been consistent?

It may just be a fluke...poor quality gas, driving a little harder, some other random variable.

Also, since it's gotten colder, you should check your tire pressure, it's probably a bit lower and that'll drop your mileage.

 

I'm on number 4 fill up but that is a good idea with the tire pressure...Ill have to check that in the morning

Thanks

 

Tire pressure was what I was going to suggest. It's tripped me up a time or two.

 

taking short trips to the corner store? letting it warm up longer due to the cold temps?

 

Winter gas and cold air. Get used to it I go from 20mpg in the summer to 13-14mpg in the winter (very short drives aswell).