One of the spark plugs on my Tahoe keeps corodding. When this happens at high speed the engine skips. Any ideas what is wrong on this truck with 115k miles? Is valve going bad or do I have a bad injector? What does it cost to fix it? Thanks.

 

Where's the corrosion? Any pics?

 

Welcome to the forum,
Corrosion at the firing tip would led me to thing moisture or coolant in the combustion chamber...how does your oil look, nice honey color or is it milky...
Are you filling the coolant over flow tank often?

If the corrosion is on the outside ( around the boot) I would suspect a splash shield is missing or your vehicle is lifted and the wheel well linings are open and allowing excess splash into the engine bay...

Just some things to consider off the top of my head, thinking like a drop of water