OK i have 91 pickup 2wd 5 speed 185k on it. it will randomly not start. it doesnt do anything. the best way to explain it is it acts like the clutch isnt pushed in when you turn the key to the start position. ive tried unplugging and plugging back in the safety switch on the clutch it does the same thing... nothing. you can hear the fuel pump pumping fuel when you turn the key but again it doesnt turn over. it will always start when u push start it. it only does it at random (usually the most inconvenient) times. im not sure what to do from here. any help would greatly be appreciated.