Re-read the directions for the break-in proceedure, this is very important. At three tanks, are not done yet. I do not have experience with that car/engine, but most any stock setting is VERY rich, sometimes to the point it wont run. Try leaning it out just a hair1/16-1/8 of a turn, and see if you can get it to run long enough to break it in. Keep in mind you want it to run very rich during break in, since the engine is so tight. Also, the plug could be bad, install a new one, just so you rule that out.
You can also do a search on break-in proceedures, there is different methods that some preffer.
Good luck