2004 Lincoln Towncar p0171 & p0174 codes

Hi, my 2004 Lincoln Town Car Ultimate just pushed out the P0171 & P0174 codes today. The scanner said 'System Too Lean Bank 1' and 'System Too Lean Bank 2'.

What does this mean? and How do I fix it?
Please help I am not very good with engines and I do not have much money to spend. I am SLOWLY trying to learn about this car as it is my lifeline of working (I own a very small chauffeur and limousine service).

Thanks in advance for all of your help,
Bruce

Sounds like unmetered air leaks, causing the engine to run lean.
Do a Google ''Auto vacuum leak smoke test''
Plastic, rubber, and gaskets will go bad with age + mileage.
Suspect the EGR, DPFE, or PCV system is sucking in Air.