I put a used 2003

I put a used 2003 grand prix 3.8 into my 98 monte carlo 3.8 i changed the intake to the plastic one ad all the other components that didnt match up. Been driving it around about 3 monthes with the engine light on. I checked the codes po171, po507 System too lean bank 1 and engine idle to high it does idle at almost 1,000 and the exhaust smells like gas. new o2 sensor but thats it and it feels like it burns through gas real quick. my MIL is on aswell