Q: Car misfire

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Do all 4 engine coils have to be the exact same shape? I've got 1 of 4 that isnt the same as the other 3.

They do not need to be replaced and be in the same shape but it sometimes is recommended to replace all of the coils at the same time since they seem to start failing one after the other in a short period of time.

A mechanic may recommend all 4 so you will not have another one fail a month from now and then another 3 months out and so on. When you replace all 4 you will have good strong spark on all coils instead of great on one and okay on the others.

The engine may run a little rough from one strong coil and 3 okay ones. It will be like replacing only 1 tire at a time. You will never have 4 new tires replacing only one at a time.

If you need to get them serviced, consider YourMechanic, as a certified technician can come diagnose your misfire and replace your remaining ignition coils if necessary. Good luck.

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