how to move engine forward to replace number 6 spark plug

Really? They built a car like that? If so they usually have iridium or at least platinum plugs. Personally I only change them if failure has a cured

Buy the proper tools need a deep well plug sockit, 3" 3/8" extension. move all hoses and wires from other plugs out of the way loosen plug it's hard to see, need an adjustable magnet to remove plug then do the reverse. take your time and make room for what your doing, don't get pissed this plug is in a tight spot. just think of this the first 5 were a snap these plugs do not last forever they should be replaced about 80 to 100k miles. the gap changes as the coils independent on each plug and have different resistances. I replaced mine on 2005 3.6 DOHC v6 at 83k most were good but three had started to burn a round hole into the tab on the plug. Replaced the plugs and the car runs like new. Make sure to gap the plugs properly