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Thunderbird 2002 - Bad Coils

My T-Bird has 67,000 miles at 57,000 it started to jump when put in reverse… felt like transmission problem… dealer said the coils are going bad and they dont know which ones until they test them … each coil to test and replace is over $100… they said just drive it until they have to replace the coils…

Isnt this bad for the engine?

Should I have them all repalced or just as they go bad?

How much to test each coil?

How much should it cost to replace each coil?



ENGINE IS 3.9L, 4V 8-CYL

3.949 CC DISPLACEMENT

91 OCTANE

FIRING ORDER 1-5-4-2-6-3-7-8

IGNITION SYSTEM “COIL ON PLUG”

COMPRESSION RATIO = 10.55:1

I received this answer from an online ford expert… but the ford dealer looked at my transmission… Any suggestions where to go for a second opinion?
From your description, it seems like it is a transmission concern because if you had a coil concern, it would be missing. If it’s “banging” going into drive, then into reverse, you may have a hydraulic concern with the solenoid pack inside the transmission. There also may be a callibration update for this concern. There is an adaptive learn strategy for shift timing and feel, but that usually is when the battery is disconnected or loses power. The PCM relearns the adaptive strategies. The cost of repair depends on what is found with diagnosis. This is all assuming the transmission from your description is the cause. If you don’t want to go back to the dealer, I am sure there are other trans repair facilities that can perform the needed diagnostics.

The most common problem for this engine is coil failure. The coils themselves cost a little under $50 each, if you do it yourself. You can pretty well determine which ones to switch by using a Ford specific code scanner to read the misfire counts for each cylinder. However, since you have a 2002, you have another problem to look for. There is a design defect with the valve cover gaskets. They leak oil into the sparkplug wells and short out the coils. If you take the coil covers off and find oil, then you need to have the gaskets replaced with the new design ones. Also, experience has taught most to go ahead and replace any and all coils that have been exposed to oil.
I would take care of that first, before looking for any transmission problems. The schedule calls for the transmission to be flushed every 150K miles, but 60K might be a more reasonable figure.