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Top Issue- 02-05 Ford Thunderbird Ignition Coils COP

Bought ena coils and ngk plugs based on the link. Was not throwing any codes but the car seemed to be sluggish. Tough getting bottom 7mm bolts near firewall on both sides. What a difference! I guess after 20 years the plugs and coils were tired. Acceleration will snap your head back now. Thanks for all the info!

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this why the 02 to 05 always having to change coil and spark plugs
Only the people that fail to fix the underlying issue causing the spark plugs & COPS to fail suffer from this. Read post #1

 
I just bought my 2002 bird this fall my mechanic said the one on the second bank went bad because of a small oil leak in the valve cover gasket. so I had him replace plugs and both gaskets.He said that will take care of it.

This is true. Our 02 with 34K miles started sputtering. Didn't look for a code, just took it to an old friend who's a Ford man. They found a leak in the gasket which was causing the problem in cylinder 5. He replaced the gasket, the coil and plug. It was thundering once again. I'll get some time in the new year and go ahead with the other bank. This time gasket, coil packs, and spark plugs all the way around.
 
2002-2005 Ford Thunderbird and Lincoln LS have a widely known issue with Ignition coils going bad and also fouling out spark plugs causing misfires
. Just by replacing these components, you may be able to bring new life to your engine!

At the time of this post, 59.30 for an entire set of Ignition Coils! Can't beat that! If you have a 2002-2005 Ford Thunderbird I would buy these just to have on hand because of the history of these going bad! Don't forget to order 8 spark plugs too because the coils foul them out!

Many people have had success with the coils above, but if you are looking for a brand name check out the Denson and NGK Coils. Click here to buy them on eBay.
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UPDATE April 2020
Here is the link for the updated part as of 04/2020 that fits better with the valve cover- https://amzn.to/31CezPd previously everyone was ordering parts galaxy which works, but is a tight fit. You can also get NGK and Denso name-brand ignition coils here.

There is a post below with installation instructions- https://forums.fordthunderbirdforum...hunderbird-ignition-coils-cop.5040/post-35040

Important- You may also have a problem with your cowl seal, wiper seal or valve cover gasket, which is causing the coils to fail! You can read more about that in this post. If you have coils problems after a few days/weeks/months it's likely not the coil, but an additional problem.


What you need to buy
1- Ignition Coils (Amazon Purchase Link)
2- 8 Spark Plugs (Amazon Purchase Link)
3- Dielectric grease (Amazon Purchase Link)
4- Valve Cover Gasket (Amazon Purchase Link) (EBay Purchase Link) (optional but highly recommended while doing the job)
5- If you need the deep & shallow 7mm sockets, here is a pack with both (Amazon Purchase Link) Also, this 1/4" swivel socket will help you get to the one hard to reach. Note: 1/4" drive makes the job easier! Some owners have reported this tool is also good for reaching the back one- https://www.amazon.com/dp/B09BTTCW3Q?tag=thunderbirdforum-20
6- This type 7mm wrench will make the job easier



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I found, that out of all them that the NGK coils had the highest heat index of all the other coils I researched, with heavier coils and stronger epoxy and better construction than the rest of them.
 
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Have a check engine light and the only thing that popped up on scanner was the throttle body but once I put the new one in there was no more codes
Did you change coils? Was it running rough before? Maybe the connectors to the coils need checked? Maybe coil connectors got connected to wrong coils? Maybe fuel injector issues? There could be more codes that don't turn on check engine light. Plugged exhaust system (e.g. cat converter)? A constant misfire normally causes Check Engine light but if car dies too fast it might not light.
Even though new, could be bad filter, bad fuel pump, bad throttle body, etc.
Usually #1 reason for rough running are bad coils.
 
A quick tip for those changing coil packs. If this was mentioned in this thread, please excuse the redundancy,

A very handy tool to have is a 1/4 inch drive, 7mm swivel socket. With the swivel and socket combined it is shorter and handier than using a regular socket and a swivel. With a six inch extension it really helps get the bolts out at the firewall end. The socket shown here has a joint that is tight enough so it will stay at the angle you set. That helps the socket find the bolt head. For example on the passenger side using the extension, you push it past a wiring harness, put the socket near the bolt, and by hand tilt it so it lines up with the bolt. Then push it on. If the socket is loose so gravity makes it flop down, it is a little harder to line up.

The brand I bought online is Tekton.Tbird 7mm swivel socket.jpg
 
Really need your help with next steps diagnosis... My brother and I are working on his creampuff, bought new in 2003 48k. In it's history it has had the coil problem you have all been mentioning, current set has been in for the past 14 years. 3 months ago was getting a sporadic 02 sensor code so replaced all 4 and reset the computer no less than 3 times. After new 02 sensors it would sporadically sputter and have an infrequent misfires. Last week noted the spark plugs were very old so we threw in a new set of NGK Iridium... Ughh, now coughing at idle, misfires when accelerating, backfires and jerky.
Next steps??? Coils again?
 
Really need your help with next steps diagnosis... My brother and I are working on his creampuff, bought new in 2003 48k. In it's history it has had the coil problem you have all been mentioning, current set has been in for the past 14 years. 3 months ago was getting a sporadic 02 sensor code so replaced all 4 and reset the computer no less than 3 times. After new 02 sensors it would sporadically sputter and have an infrequent misfires. Last week noted the spark plugs were very old so we threw in a new set of NGK Iridium... Ughh, now coughing at idle, misfires when accelerating, backfires and jerky.
Next steps??? Coils again?
Doesn't sound like you replaced any COPs. If the scanner says misfire on a pecific cylinder or two, replace the COPs. All four on that bank. They are inexpensive, and it's not difficult (get that socket and extension). If you see an oily plug exterior, come back and search for fixing the leak that leads to COP failure.

If it ran worse after the Iridiums, maybe someone on here knows of an incompatibility. That would be surprising to me but I am not a pro mechanic. Obviously know if you will be replacing the plugs before you start.
 
Have read over the years the purchase of non-OEM ignition coils by our members that some are longer than OEM coils causing a forced coil cover gap. Has any of our members purchased a correct size non OEM 02-05 3.9 lit C.O.P. Brand that fits perfect and if so, what is the “brand” name and part# if available. Thank, 2004, Merlot, William.
 
Have read over the years the purchase of non-OEM ignition coils by our members that some are longer than OEM coils causing a forced coil cover gap. Has any of our members purchased a correct size non OEM 02-05 3.9 lit C.O.P. Brand that fits perfect and if so, what is the “brand” name and part# if available. Thank, 2004, Merlot, William.
Start reading on post #1. All this has been asked and answered already.

 
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