BUYER BEWARE 
2003 Nissan Altima Sedan 2.5 4dr Sedan (2.5L 4cyl 5M)
Cat Converter Break Down-NEW ENGINE 2.5
 Loved when car when I 1st bought it. Owned for 18 months and now they will not back their products. My oil has been changed every 2500 miles all necessary maintenance. Now my check engine light went on 2 weeks ago. I take 2 Auto Zone and receive the infamous P0420 Code! I change spark plugs thinking it's minor. Nope I need an entire new engine for 4500.00. Catalytic broke down & as this happened the pieces were sucked into the engine and it ruined the rings inside the engine. SERVICE ENGINE SOON light came on 2 weeks ago! Also causing the oil consumption Problem. "Regional Specialist" NO HELP. I take care of my car.