I will try to answer both of your posts. First, buy a factory service manual (AKA: a FSM) You can get a cd-rom version from
www.zcarcreations.com. All the info you need is in the engine fuel section.
Look for any vacuum leaks. Check the air flow meter boots for holes/cracks. Trying to seal them with silicone is rather useless and makes it a crappy ghetto repair. Just replace them. Motorsports has them for a little over $20.00. Also check all the vacuum lines on the engine for cracks, dry rot, ect. You can replace most of them with 5/8" heater hose, 3/8 vac line, ect.
Get new spark plugs and wires.
Clean all the FI sensor connectors. Pay close attention to the ECU connector (located in the kick panel on driver side). Pull the connector, clean and reinstall. Clean the water temp sensor connector on the thermostat housing (not the single bullet connector that feeds the dash temp gauge).
Adjust the TPS (throttle position sensor or as the FSM calls it, the throttle position valve) per the FSM instructions
Test the afm, water temp sensor per the FSM test procedures. You will need a digital multimeter... Keep us posted.