Silver top low idle

[jdm86gtz]

First up you should check for vacuum leaks between the AFM and the head, spraying carb cleaner can help narrow down suspect areas as it will affect the running RPM.

Did you have to pull the throttle cable tight to bring the idle up? You might have a problem with the ISCV, its located (in stock form) under No.4 throttle body. You might have a dirty internal valve or a wiring issue to the valve control motor, with no throttle cable and the engine up to running temperature the idle should be steady at around 850RPM
Random photo of ISCV from Google:
http://img.photobucket.com/albums/v243/A...CF7352.jpg

Any sign that the AFM was tampered with? The black plastic cover can be forceably removed to access the internal mechanism and then clocked to alter fuel delivery. This isn't really advised though.
Did you find the O2 connector on the wiring loom?
Also do a diagnostic check by shorting pins TE1 and E1 in the diagnosis box (check the lid for pin location) and count the dash engine check light flashes.
Random picture from Google of the ecu error codes:
http://img.photobucket.com/albums/v207/k...Page3a.jpg

What size is the return pipe from the fuel pressure regulator to the fuel tank? OEM size with EFI is 7mm OD pipe.