I have a 1993 Mazda Miata that "occasionally" afte being driven for awhile will not start. It cranks over, just won't start. Sometimes when I am at an idle, in gear with clutch in or in neutral, the idle also fluctuates from 1500rpm to about 1000rmp and acts like it is going to die? Any ideas? No check engine light for the OEM to read? Thanks, Arizona Cowgirl