2006 S-type Jaguar 3.0 Base

Hello I have a 2006 s type 3.0 base Jaguar. its been giving me to main errors 1 the fuel cap and bank 1 and 2 are to rich. This is originally my mom and dads car but im now in charge or maintaining it. It does need a fuel filter change and oil change which ill be doing in the next days. I also got new e3 spark plugs and I hope a new Mass air flow sensor soon. I also know I need to replace the intake manifold O-rings 1 is leaking and I was also thinking of changing the 2 oxygen sensors when I have tested the care the 2 oxygen sensors don’t seem to be working they just come up as active. I was told I might also need to change the EGR Valve. and I was told the gas cap error or small leak might be a leak or fuel pressure sensor problem. I don’t have money to take it to be fixed or get test run and I never worked on this car other then topping fluids and change breaks. the car has 58k. I know I need to remove the manifold to change the spark plus but what gasket do I need for when I remove the manifold upper or lower? and any advice I will be happy to get.