Originally Posted by ccculbreath
whitecrystal1, I just thought of that taken what Jbrew said about it might be bad (the coil pack) Jbrew I do not like being called an idiot or a jerk. You was asked to volunteer but know one said you had too!!! I didn't know it was a play on words that you got so uptight about. You go to the parts house and ask for a coil pack for a '99 and they give you A COIL PACK that goes over the plug...Oh and you might want to proof read more often evem is not a word. And when your trying to come off being smarter than the person your writing to,it makes you look like the idiot.
LOL , spelling is one thing - at least I know what I'm talking about.... I accused you of ignorance because you doubted what I was telling you (what would you call it?)If you go to the parts store they look up your motor and then a part number..Instead of listening to you and giving you the wrong part - If they gave you a coil pack , you would be completely lost - more than you are now - You have a "coil " over each plug , not a coil pack, that's all there is to it. Why should I have to guess at what motor you have ? there three for your year.. Your the one that needs the help, don't you think you should post you motor ? u no - the one your having probs with, it would be easier to help..
COP systems as they age break down - the thermal layer gets weak and they lose there punch. The absolute best possible tune up that you can give the 99 motor is to change the COPs at the same time and for the love of God, get them Autolites out of there, they will screw up everything within time..Bad COPs will pass Primary and Secondary testing all day long .. However , this is not where they fail the majority of the time. The most common failing point during a drive cycle is the shift from Drive to Overdrive , approximately 45MPH right after the shift you'll get a misfire..You can not test this without a history reader - Mode 6 measures history per each cylinder and this can be done only at the dealership by certain qualified tech's. Global Automotive out of Florida sells F150 kits 8 COPs and 8 new Motorcraft plugs for $130 . That's a resource you won't beat - do yourself the favor....
Autolite does manufacturer Motorcraft plugs - true that, they even look identical - guess what ? the 97 -99's won't run right with the autolites because the ceramics/porcelain are of an different heat range - it varies enough to eventually cause multiple and random misfires .. I have a set of double plantinums that I can't use in my truck or any others here of that year because of the heat variance.
The 5.4L is a high tech design and is picky about the plugs you throw at it . You have the PI head design in the 99. To get full performance out of the 99 you need to run OEM Motorcrafts, NGK'S or Iradiums. If you want it fixed you need to listen up !!
What else you should look for is your heater core feed and return lines leaking over #4 , It's hard to tell sometimes because heat and air tend to dry it up fast. With age those hoses deteriorate from the inside out around the fitting and leak under pressure...
Another BIG problem is the wire harness being to close to the accumulator.. This will make the motor run very poor. I have (while the trucks running ) pulled the harness away from the accumulator and noticed a change in idle.. Your ignition system gets buggy if it's to close , trust me, I know .. Just keep it away ..
I have seen many TSB's about these problems and worked the field for many years. Credentials ? LOL , yeah , I have them , I'll tell you what - you just use your own due diligence when it comes down to your motor. I will say that I'm an engineer and a part of team that was assigned to build Fords Parabolic track in Dearborn 2004 - 2006. I just can't spell worth a sh^t..