There is a technical service bulletin for the V8 engines regarding a possible problem with the spark plug being ejected from the cylinder head, damaging the threads in the spark plug hole. If the vehicle is under warranty, cylinder head replacement is recommended. If the vehicle is out of warranty, Ford authorized the use of a specific thread insert to repair the head.Google+
Car Problem Reports
Ford Expedition TSB For Possible Ejection of Spark Plug From Cylinder Head
Ford Expedition Problem
Engines Affected: 4.6L V8, 5.4L V8
Average Mileage: 135,954 mi (11,800 mi - 230,000 mi)
Visitor, 2002 Ford Expedition, 5.4L V8, 11,800 mi
Number 5 blew while on vacation - setting in the lounge of a Ford dealership waiting for the verdict. This sucks! Ford should reapir this obvious factory defect free of charge.
Visitor, 1998 Ford Expedition, 5.4L V8
I have had spark plugs and coil pack replaced twice in a year. The second time it had to be rethreaded. Its starting to act up again.
Visitor, 1999 Ford Expedition, 5.4L V8, 110,000 mi
I have had 3 blown spark plugs. Ever since I had the plugs changed at 100K. I know now that the auto shop likely overtightened the plugs during routine maintenance. BUT the fact that it happens at all is a design flaw that shoulld have been recalled.
Visitor, 2001 Ford Expedition, 4.6L V8, 163,000 mi
My spark plug was ejected, was told that condensation from AC line drips down into the deep socket where the spark plug is located and corrodes. Happens the most on last two plugs near the firewall on the passenger side of the engine. Paid local mechanic $216 to fix with Ford approved insert, works fine now.
Visitor, 2004 Ford Expedition, 4.6L V8, 120,000 mi
Spark plug was ejected out of cylinder head stripped the thread bought a special spark plug with a boot that hade coarse thread used hi temp two part putty from auto zone. Still going 10000 miles later, but now engine light is on!
Visitor, 2004 Ford Expedition, 4.6L V8, 220,000 mi
#5 cylinder spark plug blew out - was able to drive it to the shop this morning - waiting on repair estimate
Visitor, 2000 Ford Expedition, 4.6L V8, 151,000 mi
This problem isn't fixed. Rear, driver's side spark plug blew out while driving on the highway in a construction zone. I had to drive the car for half a mile before finding an emergency pull off. You could smell the raw fuel in the passenger compartment by the time I could pull over.
Visitor, 2004 Ford Expedition, 4.6L V8, 17,000 mi
I bought this truck use I took it to my he that it head happen before and can not be fixed needs an new head
Visitor, 1999 Ford Expedition, 5.4L V8, 125,000 mi
Bought our 99 Eddie Bauer used, knew there was a stripped plug at the time, but it was supposedly repaired. We've had this truck for 2 years now, gone through 6 coils and plugs as well as 2 of these stupid "Ford Approved" repair kits. Their approved repair isn't a solution, only a band aid and shame on Ford for not acknowledging their mistake and fessing up to repairing these vehicles! My only permanent solution now is to replace the heads (of course, having a qualified machine shop re-thread the spark plug holes PROPERLY this time). In the mean time, having to deal with occasional stalls and coil burn outs has become the normal operating condition of my truck!
Shame on Ford! Shame on me too for not doing a proper google on this truck BEFORE I bought it!
Visitor, 2000 Ford Expedition, 4.6L V8, 143,000 mi
Was driving at freeway speed(65 mph) heard a kabang but vehicle continued to run, no check lights, no other weird noises. 80 miles later it throws a service engine soon light, begins to skip and miss as it drives. I get it home, I grab the code reader, plug it in, cycle it, get several that are nonsense codes(come as 'no code' but prompts one) and a spark plug 3 failure. I open hood peer inside figure aliens built this thing I couldn't find spark plugs until I broke out the Haynes repair manual and even then that was a joke for what it was buried under. Decided I can change them on a GM but this is beyond me paid the former ford dealer mechanic 300 bucks to replace my spark plugs. Number 3 had exploded, burned out and damaged the Heli coil. Heli coil was replaced. Vehicle 21k miles later still won't run smooth, service engine soon light now flashes constantly. Took it to actual Ford dealer, they insist all my spark plugs and coils are fine and cannot pull a code for what is failing. Put it on a Dyna-meter to fail it under speed, and it STILL wouldn't throw a code. All plugs and coils visually inspected, no issues. Dealer recommending replacing entire engine, at 154001 miles.