As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
(CAN) AIRCRAFT WAS SNAGGED FOR RUNNING VERY ROUGH AT IDLE, EXTENSIVE INSPECTION REVEALED THAT ALL 3 INDUCTION INTAKE TUBES OF THE ENGINE WERE CRACKED ON THEIR FLANGES. FURTHER INSPECTION SHOWED THAT THE INTAKE MANIFOLD PLENUM MOUNTING POINT WAS LOOSE CAUSING EXCESSIVE VIBRATION TO ALL 4 TUBES CAUSING THEM TO CRACK. (TC# 20190523001)