I am having distributor problems and was wondering how to rebuild one. The parts are pretty expensive. Housing approx 330, ignitor approx 100 and some other thing for about 100. How can I tell if I need a new housing? And how can I check the other components? I do have a Haynes manual, but it does not say how to check the housing. The car backfires and idles irradically. I have recently replaced all plugs, wires, distributor cap and rotor. When I replaced the distirbutor cap and rotor, distributor started squealing loudly, now it just makes a low squeal all the time. Any help would be greatly appreciated. Thanks in advance.