87 chevy camaro iroc z 305 5.0 tuned port injection

I installed an msd 6al-2 box. It ran fine for a couple days. Then it died while backing out of my driveway. It is not getting any spark. I have changed the coil, distributor rotor and cap. Had the icm checked and there is still No spark. I checked the 6al-2 box and it was Good too. The car is not throwing a code. What could be causing this?