I have 150k miles on an LT1 engine and thought I had engine knock. Preliminary diagnosis is its an exhaust leak near the engine. I will be taking my car in early next week for a thorough inspection and repair estimate. All exhaust is original so want to be equipped with some knowledge when I discuss repair options. Just before hearing the exhaust rumble the engine started sputtering like there was a fouled plug or something. With the failure of the exhaust is it possible that a plug wire was cooked and damaged? Is it possible that the opti could be damaged by an exhaust failure? Ive had sporadic activation of the check engine light. Thanks for your input

 

If the SES light has been on, you have to pull the codes. Why guess? That's what it's there for.

Exhaust will not affect the Opti. Most common leak on exhaust is the gasket between the manifold and the head. Leaks will often cause carbon track near the leak. Next location is the flange at the bottom of the manifold for the Y-pipe, on each side of the engine. It's conceivable that hot exhaust could burn a wire, but not a common problem.

You also have to check the rubber elbows for the AIR piping at the exhaust manifolds. If the check valve fails, exhaust flows out through the check valve, into the rubber hoses and melts them.

Courtesy of Shoebox:

http://shbox.com/1/diverters.jpg

 

according to the mechanic there were two plugs loose ....one of which was almost completely out. He said the loud exhaust sound was emitting from the spark plug gap. He had to rethread the plugs and reinstall. All seems fine now at a minimal cost.