[undy]

If your problem is between 3000 and 3500 rpms and your boost comes in at 3500 then this appears to be a transitional problem. You said you could "push through" and get by the problem. When you come into boost, about 3500 you go into an fuel enrichment process. Could there be an extreme lean condition between 3K and 3.5K?? That could manifest itself by the symptoms you described. When you come into boost, about 3.5K, you get that much needed fuel. Just a thought...

If your plugs are gapped too far then you would be more prone to encounter the problems under boost, vice part throttle. The dog doesn't seem to hunt.

Dave