I filled up today and figured out my gas mileage from the last tank, I'm getting 9.6mpg!

I've got a stock '83, 12a, 5spd etc.

My theory on this is that my drive to work is so short... only about 3.5 miles. My choke is out almost the entire way to work in the mornings... could this be the reason for the drastic change in gas mileage? Before I moved up for this job and did just normal driving I was getting 20+mpg.

So is this just an effect of the cold mornings and the rich mixture with the choke out or could something else be going on? Would it be better to let the car idle and warm up fully before leaving (although isn't idling like that bad for it)?

Just looking for some tips here because this is pretty pathetic.

 

m8, I cant see how idling would be bad for it? Could be wrong but I know its not good to drive your rotor and stop it before its reached operating temperature. I get better mileage in my BP

 

Something about idling the car for long periods of time as warm is bad, I don't remember the exact reasoning but I think it had something to do with water and rust. I've just always been taught its better to drive a car easy to let it warm up rather than let it idle.

My car reaches operating temp... it just happens like 0.5miles before I pull into the parking lot at work.