I am thinking 2 possible problems. IAC stuck close or the fuel vavle.

1, If the IAC stuck close, how can I test IAC is working or not? can I take the IAC out and start the engine?

2, unscrew the fuel valve cap and tried release the pressure,no gas comes out from the valve. Screw the plastic cap back. Any simple test for fuel pressure?

Any other thing I should check?

98 SVT BLACK 98 MYSTIQUE ZETEC 04 RX8 GT MT6 TITANIUM