the450r

iTrader: (1)

i have a 2002 chevrolet silverado 4.8, 5 speed, 4x4. after first start up before it warms up to operating temperature. when i push the clutch in the engine revs up. like the iac opens way too far and then stabilizes. but it takes quite a while for it to stabilizing making gear changes long or its still reving when your letting the clutch back out. its been that way ever since i have bought the truck and dual exhaust only makes it more noticable. ive looked for pcm updates and wondering if its possible to tune this out??? once the trucks warmed up it shifts like it should. i havnt seen another 4.8 5 speed to verify other trucks do this. my truck doesnt have any mods to the engine except i added cruise and dual exhaust.