A complete wiring diagram, with wiring information, for your 1999 Pontiac Grand Prix can be obtained from most General Motors dealerships. The wiring diagram and information can be found in automotive service manuals.
Some 99 Grand Prix vehicles will shift hard when it is warm. Not all of these vehicles will do this.
http://www.gp-owners.com/audio/wiring.html I hope that helps, it's not a diagram persay but at least it has all the colors. I found it looking for the same thing myself, 'cept for a '99 grand prix.
The Charcoal canister for a 99 Grand Prix Gt in in the drivers rear tire well. you have to remove wheel and then a plastic cover to get to it.
An engine compression test on a 99 Grand Prix GTP can cost $180
it starts to close and stops
In short, yes. Long Answer: Yes they truly are the same.
The low pressure port on the 99 Grand am is on the passenger side. It is right against the firewall.
It doesn't have one if its an SE.