95 Olds Cutlass Supreme; ignition won't turn over

Find the problem before randomly replacing things. Have your battery load tested. That will tell you whether its worn out or not. Your alternator can also be tested to find out if its faulty. If its been replaced it is unlikely that that's your problem, but you need to rule it out. Also your starter could be the culprit. Again, it can be tested. Spark plugs won't prevent your car from starting nor will ignition wires. Check that your battery cables are tight at both ends and that the connections are clean. Check your signal light flasher. Mine was a plastic one and the clamp that holds it had actually crushed it. That seemed to be creating some sort of a draw on the system that made it start inconsistently. I changed the flasher and all my electrical problems went away. Strange, but true. The fact that moving the shifter used to help a bit is worth investigating further after you have ruled out the main electrical components. Could be a broken wire or loose connection.

Battery..