Make sure you are getting full voltage to the coil on the primary side, The pickup coil will either work or it wont. It is a digital hall effect sensor, it wont reduce your voltage coming out of your coil. Did you replace it with a new coil? It is possible that the coil you put in is defective. The coil stores up voltage, and then when it is triggered, releases that voltage out through the distributor cap, wires and plugs. If you have a weak spark, you are either not getting full voltage to the coil, the coil isn't grounded properly, or you have resistance between the coil and the spark plugs, such as an open wire.
Just some things to check out.