My car seems to be hesitating its an 04 gtp with 9k on engine rebuild. I've been chasing this hesitation I have a cel p0300 now I left my do a little loose from rear manifold its been that way for a while with little hesitation. Is it possible I'm getting this bucking from the down pipe nit being all the way tight? I've changed plugs autolite 606 and cleaned tb this car is stock. Its loose because it sounded a little meaner while highway cruising.