Ford Truck Enthusiasts Forums - Spark Plugs for '97 Expedition 4.6L

99 EB 4.6L, 80k, I changed my plugs at ~70K and plug wires at 79K (and rechecked torque at 79K, all good)

Good Luck, recommend that you search this forum for the info (recommended plugs, gap, Etc.) You will need many sizes and lengths of extensions (I got mine at Harbor Freight, 10 pc. for ~ $8), and a lot of patients, and a few hours if this is your first time......

I also found it helpful to have thin, tight fitting wear gloves mechanic gloves, you can get some at AutoZone/Wal-Mart, Etc, for ~5$ to ~$20 because you hand will get banged up, scratched, cut...... THEY ARE A MUST, IMO, I also use rubber gloves for oil type repair work....

The plugs are very deep in the engine block, ~ 5 to 6 inches, and you have to be very creative with the #4 plug, as the coolant hoses are in the way.. you may have to drop the spark plug socket into the hole with a 3 to 6 inch extension, and then connect it to the ratchet or maybe a breaker bar type set up for added breaking torque. Spend 20 minutes looking, thinking, planning, use a mirror to find the hole.

You may want to check the plug wires at this time, I was getting a #4 Misfire code and I found a chafed wire due to rubbing on the engine somewhere.... new wires are ~ $50, and another hours to change all 8.

Be sure to replace each boot with di-electric grease, each plug with antiseize compound, and make sure each boot is probably seated... I did not fully seat the # 1 plug boot, and the engine ran crappy. I heard a clicking noise that I thought was pinging (was not sure what pinging was..) , since it would increase with speed.... and I also got a #1 misfire, and random Misfire code..... Dumb Me, the loose plug boot was sparking from the Boot to the plug or ground and ran great after a quick push.........

Hope this helps, and the above is just for info only and you should do what you think is best for your situation.. (can you tell that I work for the GOV) !!!!!!