Tighten them until they strip, then back `em off a half a turn. No, seriously, though, tighten them puppies down until you can't tighten them anymore with a regular ratchet.

 

An update - two days, >100 miles. all types of driving - NO Misfires... What did I do different? I held my mouth just right as I drove.

But seriously, I did not change a thing. Looks like I'll get a coil and try that first, and service the tranny.

I'll keep you posted.

Thanks

 

Didn't they come pregaped? Don't overtighten them! Remember these truck have spark plug blow out problems. Though mostly in the lightnings some regular f-150 do it too. it is beleived that the cause was a overtighten plug that weaken the four threads holding it in!!!!!!!!

 

I have the same problem w/ 65,000 on my 2001 f-150 supercrew 4x4 5.4. I plan to try rotating a new coil after reading these posts. This is my first trip to the board.

Sidewinder FX4 - How about that TSB #?

 

Well I ended up getting a coil and have been swapping it around for the past two days. Yesterday before heading home from work, I swapped it out at #4. I have about a 45 mile trip one way home, so if it was going to misfire again I would know. Well no misfires at all all the way home. I thought I had found the problem until this morning while I was going up a slight incline and it miss fired again! I will continue to swap the coil around. If I can't find a bad coil, I'm going to start looking at the fuel injectors.

This is frustrating especially since it ran fine before my plug change. I have pulled and rechecked spark plugs and gaps twice now. I still may buy 4 new spark plugs and change out a side and see if that fixes anything before pulling all injectors.

 

Is there any chance it is a bad fuel injector? I'm concerned about driving it in this condition. I don't want to lean out a cylinder and my daily commute is 60 mi. round trip.

Would a lean condition in one cylinder produce a code and a check engine light?

 

it should through a light, that is what the o2 sensors are far!

 

Miss is back. (didn't hold my mouth right, I guess!!!)Started the coil swap tonight. #1 appears to be good. New coil is now in #2. I'll test it on the way to work tomorrow. Carrying tools, too. I'll make another swap in teh parking lot if #2 is OK. Started there because they were easy to get at. Getting the Tranny fluid changed early next week. Anyone had experience with the replacement of fluid by flushing thru the pump? Local joint says that it will take about 45 minutes to flush and replace the fluid. $119 American. Running Exxon fuel to eliminate fuel issue. Fuel filter change to come.

Thanks for your interest. We'll either fix it or blow it up!

 

I originally replaced my transmission fluid because I thought it could be the problem. They pumped it out just like you explained. Make sure they use the correct fluid. After paying a fortune for the flush, I still had my problem. I took a little more time and watched the tach and decided I actually had a misfire problem.
My personal recommendation is to change the sparkplugs when you swap a coil. The plug change didn't help in my case, but I have read that in some cases that with a bad coil, people are seeing a fouled plug.
In my case I never a saw a code. I'm guessing that the software is set to see a certain number of misfires within a period of time. If that is not exceeded you won't ever trip a code.

I know how frustrating a misfiring engine can be. I hope everyone is able to fix this with the coil. Sure worked great for me!

 

Yeah, next would be plugs and wires, but I still say the fuel filter.

 

Coil has been in 1,2,3, & 4. Right now in 4 I have not had a miss in about 45 miles of driving. Going to test for a couple more trips. Don't know how long until I say its OK. I think that I'll put the suspected coil into #1 and see if the miss returns. Replacing the coils at this point is about a 5 minute job!

Still doing the tranny flush and fuelk filter change.

I'll let you know. Thanks for the help...

 

So far, so good. 72 hours with only three missing episodes! I think I got it!

Thanks for all your help. I couldn't done it without you!!!

 

My miss is gone! Thought I would follow up on what the problem was. After purchasing a new coil and moving it around to all eight cylinders, the truck still had a miss. Yesterday I went and bought 4 new spark plugs and changed out all the passenger side plugs. After over 60 miles worth of driving I have not had a miss and the truck seems to have its acceleration and power back.

 

Its back! Worse than ever. After several days of no misses, it starting missing very bad, worse than ever!!!Maybe a trade to a new one will solve this issue...

HELP!!!!!!

 

Did you change the fuel filter yet? That's the exact same thing that my truck was doing, and I went through several coil pack, plugs and wires before I finally changed my fuel filter and everything was fine after that.