The engine light came on my 2003 Audi A6 4.2 litre V-8 Quattro. Diagnostic test indicates insufficient air flow change while air pump switching test. probable causes: secondary air vacuum hose off or leaking, secondary air hose off or damaged,failed air pump bypass solenoid, failed diverter valve system. My question: Can any of these conditions cause excessively loud engine roar during acceleration and a loud engine idle?