Lean misfire/spark plug issues
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fivepointslow?
Joined: Apr 2010
Posts: 1
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Lean misfire/spark plug issues
Hi guys, I am new to this site and really hope someone can help me out.
I recently purchased a 1999 F150, 5.4L Lariat. It had spit out the #3 plug. I Purchased the heli-coil kit and intsalled a new coil pack- repaired it and everything was great for 400 miles until I got a misfire code on #3. I pulled the plug out and the electrode melted. I put another new plug in it and it did the same but only after a short time. I pulled it and this time the insert came with it. The electrode had melted and basically created enough junk to catch on the insert and pull it out. This totally ruined my threads. I am going to repair this with the time sert big sert kit, but need to find out what is going on before I do this. Also I might add that I put all new plugs in each cylinder, soaked and cleaned all injectors too after the first plug leaned out and burned. Here is what else I had done:
Tested all coilpacks and injectors for continuity and all tested good
new PCV valve and all new hoses
new fuel filter- good fuel pressure
Cleaned MAF with CRC MAF cleaner
The only thing I can think of is an intake gasket leak of some sort since this problem happens only on #3, I have swapped injectors and coilpacks and it still happens on #3. Maybe a burned valve? Is this common on the 5.4?
This thing is really eating my lunch. I Appreciate any help and input at all- Thank you!!
I recently purchased a 1999 F150, 5.4L Lariat. It had spit out the #3 plug. I Purchased the heli-coil kit and intsalled a new coil pack- repaired it and everything was great for 400 miles until I got a misfire code on #3. I pulled the plug out and the electrode melted. I put another new plug in it and it did the same but only after a short time. I pulled it and this time the insert came with it. The electrode had melted and basically created enough junk to catch on the insert and pull it out. This totally ruined my threads. I am going to repair this with the time sert big sert kit, but need to find out what is going on before I do this. Also I might add that I put all new plugs in each cylinder, soaked and cleaned all injectors too after the first plug leaned out and burned. Here is what else I had done:
Tested all coilpacks and injectors for continuity and all tested good
new PCV valve and all new hoses
new fuel filter- good fuel pressure
Cleaned MAF with CRC MAF cleaner
The only thing I can think of is an intake gasket leak of some sort since this problem happens only on #3, I have swapped injectors and coilpacks and it still happens on #3. Maybe a burned valve? Is this common on the 5.4?
This thing is really eating my lunch. I Appreciate any help and input at all- Thank you!!
