hello, i'm new to the 300zx forum, and have a question for you guy's. i have an 86 300zx non-turbo. sometimes when i go to start it it will fire right up, and then going down the road the security light will flash, and the car dies. when this happens it will crank over but won't start. i took the coil wire off of the distributer, and placed it by the strut tower, and cranked it over, but no spark. then turned the key off, and bang one good spark. i'm an ase certified mechanic, and it has me puzzled. i've run all kinds of tests, but nothing seems to be wrong. it's intermittent and pissing me off. any help would be greatly appreciated.