RepairPal Certified shops can diagnose and repair your 1998 BMW 740i. They provide transparent pricing with a minimum 12-month or 12,000-mile warranty on repairs and services.
This is a complex car, I would go to www.alldatadiy.com and pay a little for access to the repair manual, that is if you have mechanical experience, if not, then: here are some shops:
https://repairpal.com/bmw-repair-in-greenville-mississippi