1986 Fiero 2+2 (V6) standard 4 speed transmission

Could be the ignition key switch or the clutch safety switch (the clutch must be depressed to start).

the ignition switch on my 86 GT was under the dash, ontop the steering column, but way down from the ignition cylinder. the cylinder and switch are connected by a long skinny metal rod. this rod takes the spinning of the cylinder and pushes the switch into the different positions.

SO, when you turn the key, it pushes the rod down, and clicks the switch, maybe that rod is bent slightly, or whatever. and its not QUITE reaching the crank over switch. do the lights turn off? radio should shut up. inbetween the "on" and "run" position, the car should shut down the radio, power windows, etc. not the lights though, the lights only dim because the starter is cranking. if all these symtoms happen, but the starter doesnt crank, then either your starters bad, or the rod isnt making full push-power.

which would explain why when yuour tilted the wheel, it cranked =D

=D hope I helped!

edited to add last line about tilt