I have a 1997 GMC Sierra K1500 that is not getting spark. I changed the distributor and was running a little rough. thought maybe it was a tooth off. re adjusted it and have it set on compression at Top Dead Center. It gets a weak spark from the coil. I have replaced the ICM, Coil, Distributor, and throttle positioning Sensor, Spider Injectors, Fuel Pressure Regulator and Thermostat. Before I go and put in my new Crank Positioning Sensor, is there any other possible reasons for this. I am not really looking to purchase a new ECM. is it possible there is a bad ground along the line? Please help. I have spent a grand since it went down.