Nissan Repair: cant find the problem on 1990 maxima, time jeremy, genuine nissan parts

Question
I got new wires and plugs on my car and a week later it started sputtering.  I took it back to the shop and they said one of the plugs was dead and replaced it, and a new cap and rotor because it had cracked.  They lowered it down and drove it to the lot. When I went to drive home it wouldn't start.  Now it rarely starts.  The distributor is sparking correctly, but the responses from the cap are weak and erratic.  We have tried 3 different cap & rotors including genuine Nissan parts.  We also tried a new Ignition Control Unit (which is the Transistor Unit on Timing Cover) and still the spark is too weak to make it through the plug wires.. Any help or suggestions would be appreciated.  Thank You for your time.


Answer
Jeremy,

If the optics on the distributor are coated with old the ignition can do as you describe.  Another source of your problem might just be the coil.  Check the output of the coil for proper output.  You say it is weak so it could be the coil or the distributor optics.  Also, make sure you have good spark plugs.  I never use Bosch so make sure you have Nippondenso or NGK and that they are gapped properly.