[Cd]

I live in an apartment and cannot have a cord going out to my car.
Is there an engine warmer that is available that doesn't need to be plugged in.?
I would think that one that runs off of the cig-lighter / A/C outlet would work (but probably not even be existant, because it would of course run down the battery overnight )

What are my options ?

The reason that I want to keep my engine warm ( despite this being 90 degree Texas weather ) is that from what I have seen, my MPG reading drops as much as 4-5 MPG just by having to warm up the engine.

I noticed that in the mornings when it was cool, my mileage would be around 4-5 MPG less than when I would get off of work. When I would get off of work, the car was warm from setting in the sun all day .
Despite having more red lights and very little, if any chance to coast in neutral, the day time runs always come out higher( MPG )

I had to go into work and work an overnight shift yesterday. As a result, I went in during the day, and drove home during the cool morning hours.
So basically my results were reversed : around 41 MPG to work and 35.6 MPG on the drive home.

Could engine warm up have anything to do with my mileage fluctuations ?

I plan to put my grille block back on, but this will only help the engine warm up faster. I need something that keeps it warm all the time.