You could definitely have fuel issues to start with. There are so many potential concerns after 7 years of not being operated. Way too hard to know what's going on without hands on testing, and eliminating variables -- such as bad fuel.
RepairPal Certified shops can diagnose and repair your 1990 Cadillac Brougham. They provide transparent pricing with a minimum 12-month or 12,000-mile warranty on repairs and services.