high idle and delayed shifts; vacuum leak?

[creeper]

sooo my car is acting a little funny. I first noticed it a few weeks ago in stop and go traffic. letting off the gas at about 3-5mph it'd hold it in first at about 1100rpm right where the converter engages until i either gave it a lot more gas or stopped.

a week of no symptoms later i got a high idle rpm code, didn't really connect the two in my head so i just cleared it and continued on

now whenever i drive on the highway the rpm's never drop when i let off the gas, almost like cruise control is on. when i drop it into neutral going above 20 it revs up to 1700rpm and just sits until i put it back into drive. while i roll in drive it sits at about 1200rpm. i've also noticed it holds out on upshifts when i let off the gas a little longer and will downshift sooner when i'm braking.

the throttle body isn't sticking and is sealed well to the intake. what else should i check? throttle position sensor? vacuum leaks?

been driving for 100 or so miles since the ses light and it hasn't come back yet

any input is appreciated

[camaro2you]

Try cleaning the tb and check the iac.

[creeper]

i think we have a winner. "idle control system high idle rpm" popped up today. looks like it's the IAC. i'll see if i can find someone locally that will let me borrow theirs to see if that fixes it, thanks!

[NJ Torque]

yup... carbon built up...

my brake booster leaking also did this