Thunderbird 2002 - Bad Coils

My T-Bird has 67,000 miles at 57,000 it started to jump when put in reverse… felt like transmission problem… dealer said the coils are going bad and they dont know which ones until they test them … each coil to test and replace is over $100… they said just drive it until they have to replace the coils…

Isnt this bad for the engine?

Should I have them all repalced or just as they go bad?

How much to test each coil?

How much should it cost to replace each coil?



ENGINE IS 3.9L, 4V 8-CYL

3.949 CC DISPLACEMENT

91 OCTANE

FIRING ORDER 1-5-4-2-6-3-7-8

IGNITION SYSTEM “COIL ON PLUG”

COMPRESSION RATIO = 10.55:1