I am currently getting a check engine light with the following code "p0303". Upon researching I found on that the computer has detected that one of the engine's cylinders is not firing properly. In this case it's cylinder #3. Upon first reversing I noticed the engine stumbling, Then on acceleration the same and maybe when in low gear. I hear alot of popping from the exhaust too.
One thing I wish to mention is my car (Toyota Corolla 2006) ran fine. Yesterday I sprayed the engine bay down with a power washer but didnt aim it directly into anything or too close. A friend had a similar problem on the same car and said the coil went bad and there is a case water may be inside the cylinder? Also a spark plug might be bad as well.. I have no idea and don't want to take it to a shop and get robbed so I want some knowledge before I go.