Use a rag and sensor safe throttle cleaner on the throttle, you can try an old tooth brush, but be careful it might melt a bit. Remove the ICV and hose it out with throttle cleaner, try to keep the electrical part higher so you dont get gunk in the motor part. Also, I forgot to mention, check it over carefuly for leaks between the AFM and the throttle body, if the boot is cracked or the clamp is loose, it will cause all sorts of problems.

I check for vaccum leaks with carb cleaner, just start the engine and spray it along anything that can allow unmetered air to enter, don't forget to spray it arround the injectors incase their seals are leaky. Not all carb cleaners will affect idle alot, pop a hose off somewhere and give it a shot to see how the engine reacts so you know what to look for. You can use propane from a torch too if your too lazy to find the carb cleaner. Blow the engine compartment out frequently with compressed air to remove any pools of carb cleaner, or work the engine bay in 1/4's and allow it to breath off.

Small vaccum leaks will not cause a no start, but can cause stalling and rough idle, If you still have troubles after you fix any leaks, look into the AFM. Do a stomp test, you might have a code. clear it after you fix any vacuum leaks, and see if it comes back.