Will air in fuel line cause it to idle to high?

Yes, air in the fuel line can cause irregular engine behavior, including a high idle. When air introduces inconsistencies in fuel delivery, it can lead to improper air-fuel mixture ratiOS, which may result in the engine running lean and increasing idle speed. Additionally, air can create bubbles that disrupt fuel flow, further contributing to erratic idling. It's important to ensure the fuel system is free of air to maintain optimal engine performance.