Buick LaSabre won't start when it is cold. It runs great otherwise. on 1997 Buick LeSabre

My car will not start when it is cold. After a while, once it gets warmer, it starts and runs fine. Two (2) mechanics cannot find the problem because it only occurs early in the morning, when it is cold. Live in CA so it is not that cold.

Asked by for the 1997 Buick LeSabre
poss mass air flow sensor. these years had issues with them. do you have any eng codes