Hole in Intake Manifold Plenum on 2005 Ford Five Hundred

We recently had the engine in our Ford 500 replaced. The car had only 50,000 miles and the fuel injector failed and overloaded a cylinder causing damage to the rod and crankshaft.
We now have 2000 miles on the new engine and when driving the car yesterday, all power was lost. We had the car towed to a dealer, who found 2 holes in the pvc intake manifold plenum. It looked like something had burned through the plenum.
The techs in the service department have been unable to discover a cause for this happening.
Any insight or information you can give us is most appreciated.
Jim Van Auken

Asked by for the 2005 Ford Five Hundred
Make sure the catalytic converters aren't plugged. This could cause excessive back pressure and heat in the intake causing it to melt. Since you already had an injector fail ( I am assuming that its failure was making it inject too much fuel due to the rod and crank damage) the raw fuel would burn in the catalytic converter fusing the material inside into a solid mass, unable to pass exhaust gas.
Correct. That just happened to mine. The catalatic was plugged causing a hole in the intake manifold
did it act sluggish and chatter