Start by monitoring the battery terminal voltage during cranking - - - -hot and cold. Measure the voltage at the battery posts- - - -not the cable clamps. Then do the same test at the starter, checking voltage at the stud where the battery cable attaches and the battery ground post, also during hot and cold cranking. The voltage at both places should be the same, within less than 1/4 volt. It should not vary much from hot to cold. If any unusual readings are recorded, drop me a PM and I'll give you exact directions on how to do a "series resistance test" where the voltage drop at every connection, hot and ground, is monitored and recorded. Before you start shotgunning parts at a problem, it's essential that accurate voltage readings are taken and written down. It shows you where to look for problems.
Jerry
