For the past couple weeks every time I would be stopped at a stop sign/light, my car would rev itself a little and jerk. It wasn't hard but enough to definitely notice. Yesterday while driving, I heard a terrible sputtering sound and pulled over to discover that one of my spark plugs had blown out of the engine and dented my hood. I had it rethreaded (was stripped) and put in a new spark plug. Now the car turns on but is still having the problem when it idles at stop lights and now the check engine light came on. Also, I noticed that as soon as I got up past about 40 mph, the car jerked while driving and the higher mph the worse it got. Please help! Everyone keeps telling me different things from very serious to minor. I've never had any mechanical problems with my car and I am very worried.

2000 Honda Civic EX
83,000 miles
Regularly serviced

Thanks!

First, check for codes, which AutoZone can do for free. Be sure to record the codes they give you. Second, have the other three spark plugs replaced. The first plug likely came loose and blew out, due to not being torqued properly. The same thing could happen to the other plugs. Do the job right and replace all of the plugs.