Trouble Code Help AMB

[LowSantorin]

buddy called me saying check engine light is on, told him to get it scanned. Calls me back and says he has p0300, p0301, p0302, p0302, and p0304. Mutiple misfire and Cylinder 1-4 misfires. engine code is AMB. Not being the most familiar with this engine where is the best place to start? I was thinking plugs then coils? Possible vacum leak? What do you guys think? TIA

[bigblue]

Ask him if he had the ignition coil recall performed yet? All four sounds like a vacuum leak maybe. The only time I got all four cylinders is when I had a leak