2001 Honda Passport

Check engine light came on steady last week, had come on intermittentlyusually when raining, then would go out. Today raining, check engine light links upon acceleration.175k miles, read somewhere where it may be a spark plug issue, if that's the case is that something that a pro should do or is it possible to change out ourselves, or is the blinking check engine light something else? I've never changed them and have owned the car 3 years, put on about 90 of those 175 miles.