Just posting this as confirmation for a fix that I found while doing a search on this site: I have a '99 F-150 with 5.4L. I was driving on Freeway when, without any prior symptoms or warning, my engine developed a major stutter and loss of power. Felt almost like the transmission was clunking. Pulled over - engine didn't stall, but idled very rough (Engine light never came on). I was close to home, so got back on the freeway and made it home with the engine stuttering all the way, especially under accelleration. Checked this forum and found a couple posts regarding similar symptoms. Suggested fix was to replace the Ignition Coil on the #4 cylinder (apparently this coil gets damaged due to coolant seepage from the heater hose above it - sure enough, mine had a small leak there). I replaced the #4 Ignition Coil (and spark plug, just in case) - Problem gone!! Engine runs like new again! I also put a second clamp on the leaking hose, and plan to check it periodically for leak. Don't know what I would do without this site! Thank You to everyone who shares their knowledge on these forums!

-JM