96 Beretta wont start
!996 Beretta 3.1 V6. Engine quit on a hot day in traffic. Then after it cooled it ran fine. Then months later would not start. Replaced 4 of the plugs and wires, the crankshaft sensor, the throttle position sensor. Removed ignition computer and it checked OK at two different shops. It turns over fine and a few times almost started. But then most of the time there is NO SPARK AT ANY OF THE PLUGS. No spark at any of the 3 coils.....PLEASE HELP