Vacuum hoses
Check the condition of the vacuum hoses and connections. Often, to effectively check the hose, it must be removed from the vehicle.
Use a short piece of thin vacuum hose as a stethoscope to check for leaks in the vacuum system.
Fuel hoses
Check fuel hoses for damage or wear. Check the tightness of the hose fittings.
Metal tubes
Check that the tubes are not severely bent or pinched. Inspect the tubes for cracks or other damage. If the tube needs to be replaced, use only specially designed steel tubes.