2003 Navigator - Plug wear consistent pattern
 

2003 Navigator 5.4 Engine. 125k Title should be inconsistent wear.

Changing plugs and coil over plugs. General PITA but doable with a few tears.

Factory gap - 52-56 thousandths. As I move to the back of the engine pulling plugs, they are 70 thousandths in front and move up to 95 thousandths in the rear on pass side. Driver's rear is 87 thousandths. Almost linear in progression.

Heat related?

I have seen gaps of 125 on clapped out Windstars. They can run with fat gaps, but why the non-uniform wear?

How was getting plugs out? Need to do my 05 5.4L.

Pcv is connected to back of the intake. Those cylinders see the most oil vapors, tapering off as you work your way forward. Also with water pump in the front, those cylinders further away run hotter.

Never thought about PCV. Cool.

Two different animals. The 03 does not have spark plugs that break.

For your 2005

Use an agent in your gas across many weeks that loosens up carbon from the inside .

Remove plugs with engine hot.

Have a Lisle extractor tool on the workbench.