Replace all coils or just one

[Lyman]

Well the job is done. I paid a little more for the OE quality coils. The Jeep has a little more power than before. Idles nice and smooth. The old coils were pretty toasty. There were some where I could see witness marks of arching. They were defiantly due for replacement.

 

[2010Civic]

Nice! When was the last time the plugs were changed?

 

[Lyman]

They were changed 40,000 miles ago. Platinum plugs.

 

[Vikas]

There are some makes and models where coils are prone to die. For example 2000 era Nissan engines. For them I would recommend replacing them all as the original will die one after another.

On the other hand, on same makes an occasional coil will die but the rest can last for the life of the engine. In that case you don't have to replace them all.

 

[simple_gifts]

I was going to suggest buying two and replacing the bad one and keeping a hot swap one ready; I had a coil go bad @ 360K and just swapped one; Now I'm thinking maybe order a ready available one should another go bad. (i.e. keep one ahead of the repairs)

Of course having replaced them all, as you have done, I probably would keep one of the older ones available for a roadside repair.