Need help.
 

So it just started getting really cold here in ohio and now my rx7 when it starts it sounds like the rear rotor is dead..but once you start moving it will eventually kick in and run like normal after it back fires. could my rear rotor be starting to fail or what? I'm at a lost any help will be appreciated.

Do a compression check?

well I was very vague with that what i wanted to ask is if me not having any of the cold start assist on the motor could cause it to sound like its running on one rotor sorry.