Might be getting bad milage because of the cold dense air. There's more oxygen in it so you use more fuel...

 

if im not mistaken the TC wont lockup until you tranny temp gets up to 75degrees, and lettin it sit there at idle aint much help, when i used to daily drive mine, i used to just cruise trought the neighbor hood and by the time i got on the freeway it was just getting there... but of course this is in texas not canada!

 

Cool I've been wondering what the magic temperature was. I've driven up to 10 or 15 minutes before my TCC will lock up. As far as gas milage goes I'm pretty sure the decrease is due to the denser air aswell.

 

Exactly what I did,I love it and it works great

 

Normal. Could be worse though. Ever since reflashing my 99 with the latest and greatest GM programming, when it gets cold out it will not go past 2nd until the transmission reaches a certain temp, I believe around 80-90 degrees. It takes forever to get it there so I have to let it warm up initially for a while then take side streets until it will finally shift to third, then eventually I get OD. I need to get a performance tune done on it to fix that among other things.

On my 95 I have it set to lock the converter regaurdless of trans temp. With a higher stall I would imagine that would be really annoying driving around unlocked until it heats up.

 

the converter not locking is annoying. mine seems to do it by 60-70 degrees. about your fuel mileage. i was always under the impression that fuel composition changes in the winter months. maybe im wrong and whoever told me that was bullshitting me. but it def drops by up to 10%. ive noticed it in all my cars ive had

 

The 160* stat may be affecting your MPG's if your PCM hasn't been tuned for it, along with winter blend oxygenated gas. Our customers at the dealership complain about 2-3 MPG losses this time of year constantly.

 

I added the 160* tstat when I did the cam swap and then got it retuned for cam and tstat. I then took a long trip before it got cold with cam and 160* tstat and got about 19 mpg on the highway.
Winter time came by and I took another long trip this time I had added LT headers a built tranny with TB converter and 40,000 Tru-cool and was averageing about 16 mpg's so I guess the weather does play a big role in fuel economy

 

Absolutely

 

It also effects your performance.