The Celica GT's Throttle Body and IAC are show in the pictures below, Carbon build up in the Idle Air Control valve situated at the base of the throttle body
can result in delayed throttle response from idle. A great write up of the fix can be found on the C7Performance forum
here and here on the Celica Hobby forum
The task of removing the throttle body has one real problem area, removing the coolant hoses. The coolant is fed through the bottom of the IAC valve housing at the bottom of the throttle body
to heat up the throttle body so the throttle plate does not freeze in cold climates. The clips that secure the hoses in place need to be squeezed and pushed back up the hose, the lower clip
is especially difficult and a good selection of pliers is recommended. The IAC retaining screws are soft and very hard to remove, maybe and impact driver would have helped???
A final note, if you need to remove the IAC sensor the special 5 Point Torx bits are available on ebay.
12mm socket, (see photo/note on socket depth)
Pliers, (the more you have to choose from the better, those clips are evil)
No.1 Phillips screwdriver? (for me the IAC screws would not budge and I rounded the heads!)
A coolant hose clip, know your enemy!
Below is the Throttle body before work
Below 2 12mm sockets, their depth compared
Below Cable disconnected and part of the coolant piping.*
Throttle Body with air hose removed
Below the removed air hose!
Throttle cable removed
Removal with 12mm socket on a 6" extension
The manual gives install Torque as 21N-m 210kgf-cm 15ft-lbf
Below the 3 screws mounting the IAC to the Throttle body. These screws would not move and the heads rounded easily!!!
After re-assembly I did the coolant bleed procedure to remove trapped air from the coolant system.
This page is ONLY to show what I did to my Celica! I take NO responsibility for anything arising from information given here nor do I guarantee its correctness!