Need help ASAP in order to stay in business. My 93 Suburban tries to start but won't. Notice yesterday that when I truned the key and let go, it kept on trying to strat by itself. After about 10 sec. it started by its self. Today while going to a job, it started fine, but once I cuted it off, it tries to start but won't. Would like some idea before I take it to the shop and get raped. Thanks for any input.