I have a 99 f250 with a 5.4 and once in a while it will have a miss in low rpm under load. One day it was raining and the miss got bad and would do it all through out the rpm's then after it dried out it went back to doing it once in awhile, may be a coincidence not sure, but I noticed one of the coils had the bolt stripped out that holds it down so it was loose so I wedged a piece of rubber between it and the fuel rail and it did the same thing. I bought the truck with 181,000 and now it has 184,500 and the previous owner said he replaced the coils and plugs but not sure if thats true where should I go from here.

 

look on the drivers side of the motor 3rd plug back gets water in it from the hood seal leaking mine did found out when I changed my plugs it was dry but full of corsein clean out hole good and use plenyy of that die-elec. grease around the boot....... cross your fingers good luck

 

It started doing it again this time there was no rain. I noticed one of the coils was black and the rest had white tops and said motorcraft. I took the black one out and noticed there was no metal tip on the end of the spring like the other one I had out is this normal. I filled it with di electric grease and put it back in. I also noticed the spark plug was loose the plug was also loose on the other coil I took out

 

no loose is not good check all of them your year only has 4 threds holding it in you do not want to blow one out check them all

 

Be carefull not to break the plugs.
I haven't attempted to change mine yet but from what I've read on here they break real easy.
Maybe the PO screwed something up when he changed the plugs, if he did.

 

When I had my 99 I changed the plugs at 45K just for the head issue. It can be done with out removeing the fuel rails but you will need universals and LOTS of patience. Took me a few hours but I was careful. Needless to say at 90K I through the 3rd plug back from the front on the passenger side on my way home from fishing. Ford does use a thread replacement, sort of like a heli-coil. Cost me $500. If it were me I would check every plug.

JK

 

would is the head issue and is it ok to loctite spark plugs

 

The head issue is that these 5.4 2V engines have been blowing out spark plugs .... destroying the threads.

If you found 2 *loose* spark plugs ???! .... do them all NOW. Consider yourself lucky.

Follow correct spark plug replacement procedure.

The coils cost some money, but if everything looks screwed up on your truck, might be a good idea to have correct coils installed correctly. That and the plugs should clear up the miss.

I see sets of Motorcraft coils on ebay ... never bought them, though.

If you don't want to change all the coils, etc .... my local Advance Auto has a scanner that picks up pending light load misses.

Good luck.

 

what is the correct spark plug replacement procedure and is there anything I can do to prevent the plugs blowing out and would loctite be a bad idea

 

Loctite would be a bad idea. There is much debate on what the proper procedure is for changing plugs but many in the V10 forum (myself included) have done the following with much success on 99-02(?) modulars. After that they added threads to the head and there is a problem was getting them out in one piece.

1.) Remove coil and blow out hole with compressed air. Make sure the hole is clean BEFORE removing the plug. Lots of crap can get in under the coil.
2.) Remove plug slowly and check the head threads with a mirror for any damage. The #5 hole is real hard to see and get to and you may have to go on blind faith.
3.) Gap new plugs to .054" and use a light coating of anti-seize on the plug threads.
4.) Install new plug and torque to 168 in-lbs (14 ft-lbs).
5.) Many replace the coil boots while you have everything out as they tend to dry rot. Either way fill the boot with some dielectric grease, and reinstall.