Could be rotating the engine the wrong direction.
The engine is overheating.
when your engine is hot it causes the water to boil and the water and the anti freeze will come out of the overflow pipe.
Low fluid levels in engine.
There are pages of causes, you need to have it checked for codes.
Your mom.
That is one of many possible causes.
Your bad muffler might be part of the reason your check engine light comes on. Usually, your bad muffler causes something else to go wrong and that causes your check engine light to come on. Problems cascade.
There is a problem with the emissions system.
you have a problem with your engine and and its emissions. take it to auto zone for a free check.
Have the code read, that will tell you.
A problem with the emissions system.
your oxygensensor is bad ,its screwed in to your exhaust manifold, about 30.00