What has already been done? All 6 plugs been replaced and both coil packs replcaed with new or known working one's?
The first thing to do is the pedal trick, that will give you the fault codes. 0300 means random missfire detected which is expected. Then you will get some or all of the following, 0301,0303,0305,0302,0304,0306. The last number refers to the cylinder. 1-3-5 bank, or the 2-4-6 bank could be at fault.
So, do the pedal trick and see what codes you get, then repost back with the codes and we'll see what we can do then