Thread: Help!

Ok so my 02 n/a 40th grand prix is giving me some issues. First off it just recently turned over to 100,000 miles. I have noticed that the car is very slugish at WOT and i think i may have heard it back fire once but im not to sure. The other thing is that if i WOT the car it will hold the gear for a bit and then i think it is going to shift but sometimes it will hold it longer than i thought it was going to. Just so you guys know i bought this car off of my nana so she took it to the dealer regularly and never beat on it. She was the only owner Also i have kept up with regular oil changes and use full synthetic. My first though is it could be a clogged CAT which would be an easy fix cause im putting SD headers on with the included race pipe. But other than that im out of ideas. If it helps my mods are cone intake on TB and dynomax mufflers. Headers aren't installed yet

Nope i never cleaned the TB but i have seafoamed it. The little butterfly piece in the TB looks shiny but do you think i should still take it apart? If so what parts will i need for taking it apart and putting it back on (like gaskets and stuff)?

I put some in the oil before an oil change and then some in gas tank. Then i put the rest in the brake booster line. Is there a write-up for cleaning a TB i have never done it before and i would like to clean it the best i can so my car will be working perfectly

Plugs i haven't changed, im waiting to do that when i do the headers. Also could someone give me a lesson on why a dirty TB would be bad lol?

Come on people I really need some help with this I need more opinions!