You have to be sure that they have not already been replaced. Some people replaced them with the after-market wire that do not have removable ends. In which case, you will have to replace the set.
If your wires are factory, just scope the engine and find out which tips ar at fault and replace them with factory originals.
They just screw off the end of the wire. On the end of the wire, you will find a brass tip that is threaded. I open the boot and spray some silicone lube before unscrewing.
1991 GMC Syclone
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