Mustang hesitating
 

Maybe someone can help me with this. I recently put the passenger side head and timing back on my 2003 gt and I was running it today and noticed that when running in any gear at about 2000 rpm the engine starts to stumble or hesitate, but you gun it, the car responds. The car is also emitting a strange odor, kind of like leaking antifreeze but a bit I'different. Hear is what I did to the car. I bought new cam gears, new head gasket and bolts for the passenger side, head and followed the tightening procedure as indicated in the manual. when I was setting the head and inserting the bolts i noticed that there was antifreeze in the threads of the head bolts. I tried to take out as much as I could but when the bolts went in you cld here liquid splashing around in there. Could it be that the antifreeze that was being pushed out is fouling my plugs and that is why there is the strong odor and the plugs are wet and that is why it is hesitating? Or do I have take that head off and redo the work with new gasket and head bolts? Someone please advise. I also Did not have the head surfaced when it was off.