Expedition XLT 5.4L V8

• Automatic transmission
• 77,750 miles

well, i wrote on here a few months ago about my truck sputtering when i gave it gas...auto zone told me cylinder #5 was misfiring and i needed a new coil pack...i took it to a local car dealer where i knew someone who worked there and had him take a look at it...he said it wasn't a coil pack, so i had him switch #1 and #5 just to see what happens...it did fine for about 3 hours, then it went back just like it had been doing...i drove it like that for about a month or so until my check engine light came back on...so i took it to a shop called tuffy...they did the diagnostics check on it and it said the same thing (not sure if they cleared the code from the first time or not)...they said i need a new coil pack on number five. so this time i said ok and went and bought a brand new coil pack, i took it back to them and let them put it on...guess what, still throwing code and didn't fix problem...so then i went and bought a new plug for #5 and replaced the old one...still nothing...checked all my injectors, they were fine...checked everything i knew to and still nothing...tuffy finally gave up and told me they had no idea what was wrong with my truck...it is still doing it...i have no idea myself but i do know it is hurting my gas and sounds like crap whenever i give it gas...if anyone has any ideas what it could be or any suggestions on how to fix it, i would greatly appreciate it...you can email me directly at shaunmcfd@comcast.net...thank you