1991 lesabre stating probs

car used to die while i was just driving (about once a week). took it in they replaced cam sensor and exactly one week later it started doing it again. took it back in and they changed crank sensor. exactly one week later the car wouldn,t start. the next day it started fine and the mech said he couldn't find anything wrong with it. now the car car only starts every once and awhile. last nite it would't start so i left it over nite it started find this morning,three hours later tryed it again and it didn't start.mech said they have check everything and they are stumped. if anyone has any suggestions i would be very greatful.

I would check the engine compression, if they did a thorough check on the ignition system. If the engine seems to be turning over faster than normal then you could have a timing issue.:2cents: