I have a 2004 T Bird. With 14,200 miles and started missing under acceleration. Took it to my Ford Dealer in Stockton, Ca.
It was two coils and the window washer container and they replaced them. Gave me a new Mustang to drive home. I live 65 miles away from the dealer. No charge for anything except the gas I used.
There is a Ford warranty on the 2002--2004 Thunderbirds for 100,000 miles or 10 years. The Dealer was great. Said come back if the problem recurs. No Charge just a handshake.
Cy in CA.