Check Engine Light and Engine Misfire on Ford Thunderbird

The valve cover gaskets may leak oil into the spark plug wells, shorting out the spark plugs, causing a misfire, and illuminating the Check Engine Light. Commonly the spark plugs and ignition coils or wires will require replacement, along with resealing the valve cover to correct this concern.

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Average mileage: 77,750 (35,000–175,000)
Engine affected: 4.6L V8
5 model years affected: 1997, 2002, 2003, 2004, more2005
26 people reported this problem
15 people shared problem details
2005 Ford Thunderbird110,000
oil in spark plug wells, causes random misfires.
replace coils frequently
Car idle choppy. Check engine light came on. Problem waS leaking gasket filled spark plug wells with oil. Causing arc. Costing 1,100. Ouch
Check engine light came on, took to Ford, EGR valve needed to be replaced, $500. Drove car 5 miles, check engine light came on, took it back to Ford, oil leak in valve cover gasket #3 cylinder spark plug and coil, $800. I've already had 8 coils replaced one by one over the years (bought my car in 2005), this makes number 9. I belong to a TBird car club, will be sure to pass this info on to them.
replaced 4 cop's over 3 yrs
Oil in spark plug wells. Cleaned and checked plugs, wells, and coils. Will have to replace Valve Cover Garkets at some point. Running well for now. Dealer told me that there was moisture (water) under coil covers and that I needed new retro-fitted coil covers and seal by wiper motor @ a cost of $475.00. Checked it myself, no moisture but oil in wells. Took 2 1/2 hours to clean and replace coil covers. Now I have to replace Valve Cover Gaskets next.
3 plugs misfiring, found that oil leaking into spark plug wells, expensive $1200 repair. Car is always garaged, driven less than 5,000 miles a year, and serviced regularly. Not happy.
Not fixed yet, 8 plugs misfiring, you can figure out the rest:(
misfiring engine, engine light came on. Took it in for diagnostic and found #1 spark and ignition coil defective due to water in spark plug, cost of repair, $459.00. Same thing happened 5 months later with the #3 plug and coil. Definately a poor design by Ford... Now the engine is doing an occasional miss and I'm sure another coil and plug are to blame....
Misfire, rough idle and driving. Oil leak into valves due to valve cover gasket failure. Replace coils and gaskets. $1200. This is apparently a known (too well) issue with 2002 Ford Thunderbirds, warping valve covers due to engine heat also leads to the leaks.
The check engine light came on, 3 coils needed replacing. This happened six months previous as well - had to replace 1 then. Has cost about $1600 so far...
6 out of 8 coils got oil soak ed and started missfiring
just happened replaced plugs and coil, cleaned area and so far so good will be scheduling o-rings and gasket replacement soon.
1997 Ford Thunderbird103,335
just bought the car a mile down the road check engine light came on ,went to go do a tune up on it pulled 3rd plug wire on passanger side and it was floating in oil looked around the top of engine noticed oil comming from valve cover
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The intake and valve cover gaskets may leak oil.
Water or oil may enter into the ignition coil cover and the spark plug bore, causing a misfire...

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