New Lancer Help Please
 

I just purchased a 2002 lancer es model 2.0l Auto. I pulled the code and I got a p0304b. The car doesnt miss at all when its not under a load. The second you put into drive and start to accelerate it misses really bad , then seems to level out once it gets momentum going. just curious as to what It could be: Plugs, coil, injector ect? or what else I should look into, and what are the common issues. I havent pulled the plugs yet, I might do that tomorrow. Thanks in advance for all the feed back and help.