Ok I have a 1985 GMC Sierra Classic(I just call it a Chevy). The engine was rebuilt maybe 2 or 3 years ago. It has 97000 on it. Not one spot of rust on it. For some reason after i'm done driving around when I put it into park and let it idle, sometimes the exhaust is smoking out of one pipe, Why? My friend said that one half of the motor isn't firing right. Ok another problem is when it is cold outside and I just start the truck form sitting all night, I put it into drive and it doesnt go, it acts like it is still in park or neutral. So I have to rock it a couple of times to get it going( I know the brakes aren't frozen ) Why is that?

 

okay, either your Tranny needs fluid, or there's another problem with it.

The smoking out of one pipe, duals I'd imagine? Would be because of some sticky lifters and/or bad seals. You're burning oil in one side of the motor.

 

It's firing just fine, like I said, it's either stick lifters and/or bad seals.