The Federal Emissions Warranty can cover emissions related component repairs for vehicles up to 8 years old or up to 80,000 miles, whichever comes first.
Based on the information you've provided we do not believe your 1986 Mitsubishi Gallant falls under either California or Federal Emissions Warranty coverage. If it did however, both parts and labor should be covered. Please consult a local Mitsubishi dealer for more information.