I have a pre 03/04 five hundred just realized this makes a difference. Anyways my gas mileage is shit but with ac. I recently changed the 2 catalytic converters and o2 on another car gas mileage increased 25%. The replacement converters were significantly smaller than originals.
Can this help with my 20 yr old car? Also I keep finding it has 1 or 3 catalytic converters. Can you help with this also? It's awd se
Saturday, July 12th, 2025 AT 3:22 PM