Changed thermostat, grand prix gt, check engine light still on?!?

Yes it will bolt in.

enter this into your computers search browser
and press return

"ignition diagram for 2000 Pontiac grand prix gt 3.8l"

check for a bad relay. i had a 2000 grand am se
that was throwing a security light for some reason.
i was losing power in the beginning and then one day i was driving and the engine sputtered and died. come to find out it was the fuel pump telar that had gone bad. the secirity light went off after rrplacment. drove great aftrr. there is also you can do with turning the key to acc for like 15 min. idk look it up

Hello, kevans222 and thank you for asking your question on Fixya!

Here is a simple process that will walk you through a few steps that will pinpoint the overheating problem on your 2002 Pontiac Grand Prix, without even using any tools. It has helped millions of people, and I am certain that it will help you, because I wrote it for people in your exact situation.
How to diagnose your overheating 2002 Pontiac Grand Prix

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Thanks for the vote, and good luck!

Yes. Remove the housing (not the hose) and you'll find the thermostat.

I have a 2000 Grand Prix 3.8
the transmission shifts fine till it gets hot then it starts shifting hard into gears can anyone tell me what might be causing this.

maf sensor

Under the air cleaner assembly.

http://en.wikipedia.org/wiki/Pontiac_Grand_Am
http://en.wikipedia.org/wiki/Pontiac_Grand_Prix

By using a scanner only. Older cars you could disconnect the battery and it would reset but with obd 2 cars that doesn't work.