How can you tell when a spark plug boot is bad? engine spits like a spark plug is bad but the plugs are new. Any suggestions fellow hobbiest.



Thank you

 

You can test them. Is your car throwing any codes?

 

Could be a bad boot or a bad coil pack.

If you are sure it is a spark issue and the plugs are good, you might try buying a new, complete COP. It will come with the coil and the boot. Then, swap each of the old ones out one at a time until the problem goes away. If you have two bad ones, you may not find either of them this way though.

You can also have the COP bench tested.

I had a problem like this last summer. Was a pain to resolve and turned out to be two bad COP's. One was obviously bad and the other was harder to find.

You can also try cleaning the boots and the coils with some contact cleaner. The coils can arc and leave a residue in the boot that can cause a miss.