my 05 cs (17k miles) started acting like it had bad fuel. this happened for about 5 minutes. whenever tack over 4k it started bucking. then it was fine. drove it 200 miles to dealer and was fine. dealer said fuel pump went and it has a extra pump that took over. needs 2 weeks to get new pump but said its fine to use. does this make any sense? if true, why would pump go after 17k miles?