12V , ID "GIB". See OASIS or TSB 02-21-08 for repair procedures for cracks at the NVH bracket on 1997/1999 E/ME vehicles. Do not replace the catalyst assembly for a crack in this area to which the TSB can be used for repair., 12 valve, unleaded fuel, AX4S, 49 States (Federal) & Canadian requirements, with a 1 3/4" neck, FROM 3/05/97