RPM issues on my 2015 Chevy Tahoe

Clean the throttle body out. Use brake clean on a rag. You might need a long flat tipped screwdriver wrapped with a rag doused in brake clean. Open the throttle manually, uses a tooth brush around the return springs. If that doesn't work you might have to take it to the shop and have them do it professionally.

Throttle cable or throttle body is dirty and sticking , just need to clean em , a little carb. cleaner will do the trick.