2004 Cadillac XLR Question: my check engine light comes on my 04 XLR dealer codes are P0101, P0171, P0174

I have a aftermarket top and bottom mesh grille and aftermarket exhaust system only from the catback. Caddy dealer fills the problem is due to the mesh grill not getting enough airflow i don't beleave that's the problem and i don't have the OEM grille or nor the OEM exhaust to prove them wrong the car is still covered under warr. I fill it due to vacuum leak. thanks Derrick