This needs to be said. There are things on these engines that shouldn't ever need to be adjusted and never should be because they are set at the factory. And things you can rule out being problematic at WOT and Idle.
Idle Speed - this setting is the screw by the throttlebody under the rubber cap. The computer automatically controls the idle speed so this screw doesn't ever need to be messed with. If you think your idle is too slow/fast, first, check the idle speed with a REAL tach, not the one in the gauge cluster this one is wrong i can almost garuntee that. if it is still low/fast check your Idle Speed Control Valve (iscv)(the motor looking thing protruding from the intake manifold twards the front. Put a screw driver on it and your ear to the butt of the driver if it clicks it's working fine. and also if you turn off the engine and you hear a series of clicks from the engine bay it's working fine).
Idle Mixture - the computer is in closed loop mode at cold idle. If the engine is running rich it's normal. If it's running rich/lean durring warm idle you prolly need a new o2 sensor or it's a fuel delivery system problem or the ecu doesn't know it's warm.
At cold Idle and WOT the following parts can't be giving you trouble because they aren't used:
Mass Airflow Meter(AFM)
Oxygen Sensor(OXS) (the oxygen sensor can never throw the computer off so far that the engine won't run. it'll detect the abnormallity and discontinue use of the o2 sensor. this will make it go rich but my bad o2 sensor never caused my car any troubles.)
Want to know how far off your tach is? In normal mode the engine shifts at 5200 at WOT and 5600 in PWR. The engine shifts out of first 300 rpm later then any other gear no matter how far down the pedal is pressed.
i've found that only at the 1k mark is the tach correct. anything else and it's off by about 150(below 1k mark)-400rpm(near redline).
Hope this helps people rule things out when they are troubleshooting. I know there are more things that don't need adjusted and more sensors that aren't used but i'm a lil out of it. Add any of them if you can think of them before i add them.