I am definitely a newbie, and don't know if this would cause bad mileage, but even it didnt it wouldn't hurt to check out. I feel weird giving advice and someone please correct me if I'm wrong, but I think the 85's from california had a trap oxidizer that can still be fixed/repaired under recall...found this thread and i'm sure there is more if you search for trap oxidizer or 1985 or something to that effect. http://www.peachparts.com/shopforum/showthread.php?threadid=10014&highlight=1985+california+recall