What may cause the temperature to rise on when sitting still but when driving temperature is normal?
Your cooing system.
Check for your hoses collapsing. Also check that radiator fins are clean. Are all your radiator shrouds still in place?
could be a clogged radiator
Looking for a Used Monte Carlo in your area?
CarGurus has 1,402 nationwide Monte Carlo listings starting at $2,500.
Search Chevrolet Monte Carlo Questions
Chevrolet Monte Carlo Experts