Coil #3 Failed - Replace All or Replace One?

[surfajl77]

Note: 2009 Yaris is currently at 408K.

After my last episode on 10/21 where my alternator failed and left me stranded until a tow arrived 4.5 hours later, I was faced with yet another issue last night that left me in a similar situation.

On the way home from work, the engine started jerking and misfiring, so I immediately put on the hazards and was able to get off of the road and pull into a a nearby Starbucks. I had this happen to me a couple of years ago, which ended up being a failure of coil #2 - so I suspected a similar diagnosis. I requested to be towed to the Firestone near my house.

They called me and confirmed that it was indeed a coil failure, this time #3. However, unlike the last time this happened, back when my car was in the high 200s, they are now recommending that all four coils be replaced due to a risk of the others also failing.

Am I being ripped off? I mean, the amount of time between this coil failing and the previous coil failing is like....four years.

[mitch9521]

Coils are cheap, may as well replace all 4.

[IndestructibleYaris]

replace 1, parts are cheap but your time isn't, and they don't all fail at once, never

[komichal]

parts are cheap but your time isn't

I agree, but it seems to me that it makes actually better sense to replace all at once as it takes just a few more minutes once you are digged under the hood - then you know that you have it all sorted out and it will not fail in the least convenient time (freezing winter outside, summer vacation somewhere, desperate need to drive a relative with broken ankle to a hospital...) to spoil your situation.

[komichal]

On a related note - can the coil actually get worn-out to a fact that it impacts the engine performance but does not produce an error code?

My 2007 64kW engine with 205000 km (original coils) is running realiably but it is just not as "live" as it used to be. Compression is ok. New iridium plugs helped a bit but the feeling is still a lot worse comparing to another similar Yaris I recently drove (same engine). Regularly changing fluids, filters...

[bronsin]

Next time you get a P00123 or four don’t bring it to the dealer just swap the coils around to find the bad one do it yourself.

[ex-x-fire]

Yep, a code reader and a spare coil is one thing I keep in the car.

[mitch9521]

replace 1, parts are cheap but your time isn't, and they don't all fail at once, never

Its literally a 5 minute job to replace all 4 on a 1NZ-FE lol

[remcafee]

i like using oem coils, aftermarket ones dont have good contact on the bottom boots that grip the spark plug, just buy 1 at a time, and buy OEM coils