Mine were stuck also, but as suggested twisting first seemed to break the stuck wires loose. Vehicle had 112,000 miles with iridium plugs. I thought just a good time to swap them out, expecting plugs to be shot. The actually still looked very good. No improvement on mileage, wonder why I wasted my time.

 

This forum frequently suggests silicone grease inside the boot BEFORE replacing the wires. Makes me wonder why Chevrolet didn't do that? 10 cents worth of silicone
on the boots when the engine was built by GM would save you, me and every mechanic in the world a lot needless time trying to wrestle those damn boots off after
100,000 miles. Duh?

 

6-8 wires PER vehicle times????=$$$$$$$$$$

 

When they won't come loose, then it's time for new plug wires. It will be when I'm through with them.

 

You can replace the spark plug wires. A good spark plug wire can solve this problem easily. ACDeclo can be a good option. You can check this guide for more good option https://toolinggeek.com/best-spark-p...or-6-0-vortec/