Attempting to adjust the timing yourself will likely damage the engine or the PCM. The PCM constantly monitors various engine sensors and adjusts the timing automatically for optimal performance and emissions.
If you're experiencing problems that you suspect are related to ignition timing (like poor performance, misfires, or rough running), you should:
1. Have the vehicle diagnosed: Take it to a mechanic or auto parts store that can read the OBD-II trouble codes. This will pinpoint the actual problem. Many problems that *feel* like timing issues are actually caused by other things, such as faulty sensors (crankshaft position sensor, camshaft position sensor, etc.), a failing ignition coil, bad spark plugs or wires, or even low fuel pressure.
2. Don't attempt DIY timing adjustments: As stated earlier, there's no user-adjustable timing mechanism on this engine. Any attempt to manually adjust it will likely result in damage and costly repairs.
In short, the answer is: You don't. The system is computer-controlled, and you should rely on professional diagnostics and repairs.
