I’ve been having this problem for a while after fixing my leaking distributor which probably damaged my starter. I just replaced the starter today, and it’s been firing up every time. Before I replaced the starter, I replaced all the other components mentioned on other threads: the VSS, ignition switch wiring and even the battery. After comparing the new starter with the original OEM starter, I found a chip near the spade connector which probably affected the connection (along with the oil that was dripping on it). This little connector probably was affecting the speedometer and inconsistent starting.