1990 Buick Lesabre HARD STARTING AFTER 8 IDLE HOURS

Electrical problem
1990 Buick Lesabre 6 cyl Two Wheel Drive Automatic 130K miles

MY 1990 BUICK LESABRE STARTS HARD ONLY WHEN
IT'S BELOW 45 DEGREES, DAMP & AFTER IT'S BEEN
IDLE FOR 8 OR MORE HOURS. SYMPTOMS? MISFIRING, TURNS OVER BUT NO FIRING, BACKFIRES, ALMOST FIRES BUT NOT QUITE. SAD TO SAY, AFTER 7 OR 8 MINUTES, IT MAY FINALLY FIRE OR OR I MAY SPUTTER & FUME & HAVE IT TOWED. THIS IS ABSOLUTELY UNPREDICTABLE. SOMETIMES IT STARTS & OTHER TIMES IT WON'T.
THIS PROBLEM NEVER OCURRS WHEN IT'S ABOVE 50 DEGREES & LENGTH OF IDLE TIME IS NOT EVEN A FACTOR. ONCE THE CAR IS RUNNING THERE ARE NO STARTING PROBLEMS REGARDLESS OF HOW MANY TIMES THE ENGINE IS SHUT OFF EVEN IF IT'S MINUS 10 DEGREES! IF YOU SOLVE THIS ONE THEN YOU DESERVE MY LOTTERY WINNINGS! RADIO RON