94 olds achieva
 

I just replaced the tranny because i thought that it was the problem with no power but that was not the problem.I need to know what it could be if there is no power in drive but when i start out in 2nd it's fine, i have to manualy shift it.The other problem is that when i let go of the gas the tackomiter goes down to 1000 rpm's.What would cause this?