Q: Loud roaring sound from engine when accelerating

It sounds like you have an exhaust leak. An exhaust leak can cause a Check Engine Light. It will give the O2 sensors a false reading. The exhaust runs nearly the length of the car and consists of two catalytic converters, three mufflers and piping. It can leak anywhere and usually leaks due to rust. Only the broken section needs replacing, but it will need to be inspected to see what needs replaced, and what parts can still be used. Replacement exhaust is a lower quality than factory. Factory exhaust is very expensive when it is available. The Check Engine Light should go out if the exhaust leak was the cause, so don’t pay extra to have it diagnosed. If it remains on after a week, then have it diagnosed.