my 97 eldorado was running great and suddenly it started running rough it idles rough in a idle position but when accelerating at higher speeds seems fine had it diag and said 5 cylinder was misfiring changed #5 sparkplug and still running rough please he

Check or change out the coil pack...should be located on the top left side of the engine...changing out one may help, but it's best to change out all four...

To the responder...are you referring to the ignition coil pack? Sorry not so savvy about cars.

Sounds to me like you may have a coil pack malfunctioning It is the the ignition coil pack v8s have 4 and 6s have three I think