Any suggestions on starting problem?

[src76ta]

I'll start at the beginning so as not to miss anything. I purchased this TTA a little over a year ago with 67 miles on it.The tank had been dropped and I am assuming cleaned. The car ran ok but had a knock under boost and a slight miss. I contacted a local turbo buick expert to look at possible problems. He checked for codes and found none. At his suggestion we replaced the fuel filter and replaced the injectors with a stock set that had been rebuilt and flow mathced. This elimanated the knock but the car developed an intermitten no start problem. He unplugged the crank sensor with the car running to eliminate it as a possoble problem. Since then I have replaced the VATS module,swapped out a known good coil pack and module,no change. Tried a known computer,no change.The troubling thing is that between these steps, the car may start at any given time. The only thing that seems suspect is that when the car cranks but won't fire, if I pull the ECM fuse and reinstall it the car fires. It may fire the next six times and then crank and not start. The only other hint is that it seems to crank for two or three seconds before starting when it does start. I would appreciate any help that the TTA following could provide. I took the car to TA nationals last year and the car started and ran but when I shut it down to go through tech it would not refire. Talk about red faced. Please help.