How can you tell if coils are bad.

[mjh112]

I changed out 2 coils last summer. They were the only 2 that the tester said were bad. Unfortunately, at that time I did not realize that it might be a good time to change the gaskets that allowed the leak in the first place. Long story short, the engine is doing the same thing-hesitating, power loss, etc. My question, is there any way to test the old coils to see if they were indeed bad? I just assumed they needed replaced due to the fact the spark plug was filled with engine oil.

 

[Amoxi]

If your engine light is on just take it to Autozone or something and pull the code. It'll tell you which is bad. First time for me was #6 and #4. This last time a month ago was #8. Problem felt the same though.

 

[Fla02LS]

What if there are no error codes or light on ?

 

[97stscaddy]

If there is a misfire there should be a light on. If there isnt a light then it might be a vacuum leak.

 

[Icewood]

If there is a misfire there should be a light on. If there isnt a light then it might be a vacuum leak.

My light was on , until I replaced all my plugs. Now that they have all been replaced the car drives alot better ( less power loss etc.) but it does still idle rough at times....but no light is on...

what could it be?