1999 V6 Passat - stutters on accelleration

I live in Richmond, Va and have a 99 Passat. I have put 10,000 miles on it since January and didn't have any trouble until last week. I am getting the 303 error code as well. I have replaced the ignition coils, plugs, and wires. I have heard tales of the same thing happening due to a battery with a dead cell so I replaced it - still no resolution. I was then going to replace the injectors but it doesn't look like that corrects the problem. Has anyone figured out what the cause of this issue is? Should I just clear the codes and trade it in?

Also it seems to misfire more frequently when cold. I have also noticed it doesn't seem to misfire as much at speeds above 70mph. Any ideas or help would be appreciated at this point.

Dave

i am having the same problem with my 05 passat 1.8T. I have replaced the spark plugs and all of the ignition coils. It misfires only when accelerating quickly.

whats the stutter like? i have a 96 vr6 passat and when i'd start out from a stand still position id have to slowly give it gas and itd be fine, but if i gave it too much it would kinda stutter or bog down. after 1st gear or higher rpms if i gave it alot of gas it would bog donw but wouldnt stutter. by stutter i mean go then sorta lose power then go. if that makes sense. any who, today i noticed the bigger diamtere plastic fitting coming from the air box was loose and not necessarily connected to the fitting it should have been. connected it and it got rid of the problem. not sure if this is the same issue but yea. its an idea?

i have replaced all of the ignition coils. I had platnum plugs in and I heard that they wouldnt work with the turbo and I replaced them with copper plugs and it didnt fix the problem. Again, it only seems to misfire when accelerating quickly at higher RPMs. The check engine light stays on but when it misfires, it blinks. The codes say that there are random multiple misfires and misfires in cyliners 1-4. Also, it says that there could be a vaccum leak. What could be the problem or how can i diagnose it?