Automoatic trans over reving when motor and trans reaches optimal temperature. Then when put in park,, idle is much higher than normal. Someone please help. The "Service Engine Soon" light is on but I got that checked out and it is the catalytic converter, so I do not think that is the problem. Is the problem inside the transmission or is it something minor?
Sometimes I find myself cruising down city streets in 2nd gear at 40 mph and it will not shift unless I let off the gas. If I shift the car manually from 1st to 2nd it seems fine.
SOMEONE PLEASE RESPOND TY

Transam_00@sbcglobal.net

2000 Trans Am - auto
SLP loudmouth
SLP cold air intake
K&N filter
Mass Air Flow sensor from a 99 Camaro SS (is this bad?)
Raptor Hood from Gadget Motorsports

What are some other mods that could really get me moving on the city streets?