So I kept telling myself after some brake work, that I would get back to diagnosing electric/fuel/running like crap issues with my car again...looks like things are going wrong already!

To start things off, the engine (305 TBI) had not been started in 4-5 weeks or so. Ever since I've bought this car, it's always cranked up pretty slowly when first trying to start it for the day, or after it's been shut off for awhile, and I never did get around to figuring it out/fixing it, due to addressing other problems first. Well now it doesn't seem to want to start at all. The engine will start to slowly crank over when the key is turned, but after a few seconds of cranking, a loud, slow clicking sound can be heard, and it the engine cranking gets slower.

So far, I've checked the battery out (bought new several months back), and there's nothing wrong with it. Voltage is perfect. The alternator was one of the very few things the PO actually changed on the car before I bought it. Cap & Rotor was also replaced about a year ago. I've been told the starter/selenoid could be toast, but I've also heard that if you hear clicking, then the starter isn't the problem? Is it common for the selenoid alone to be at fault, and is it worth replacing only the selenoid if so?

 

If you are confident the battery is up to snuff (properly charged, no dead cell, etc.):

Check all your battery cable connections - as in, take them apart, brush them clean, retighten them properly. Both ends, the battery ends and the engine ends (of course, have the ground cable disconnected before removing the positive cable from the starter). If the cables are corroded, replace them. Using larger gauge than stock isn't a bad idea.