2006 elantra misfiring codes
 

Please Help. I had my elantra worked on because of check engine light was on. I was getting 0300, 0301, 0304 misfiring codes. The mechanic said it was my fuel injectors, so I had them replaced and now the car is blowing white smoke out the exhaust. The mechanic told me I have a blown head gasket. Is it possible for that to happen when it was doing that before the fuel injectors were replaced?

A misfire is usually ignition. Check the ignition system (plugs, wires, coils, etc)

06 elantra
 

Plugs wires and coils were all replaced and I was still getting the same codes. That was the reason I took it to the mechanic. He told me 2 of my fuel injectors were leaking, so I had him replace them. Now he is telling me that when he started the car the next morning, white smoke was coming out of the exhaust. He used a block tester(?) and told me that the head gasket is bad. Before replacing the fuel injectors I didn't have white smoke coming out of the exhaust. I am concerned that what he did might have caused more problems. Is that possible?