There is a hard plastic hose that comes out of the manifold & goes to the other side of the manifold. This keeps melting. What is the problem & what is this hose called?

A female trying to help hubby out
Kathy

 

Your AIR (air injection reaction) system check valves are bad and need to be replaced. This system is an emissions device that forces fresh air into the exhaust stream to increase catalytic converter efficiency. If the check valves go bad, exhaust gas will flow back towards the pump when the pump is not on and melt the rubber hoses.