I HAVE A 97 CHEVY S-10, WITH THE 2.2 4 CYL. IN THE PAST FEW WEEKS AFTER SITTING OVERNIGHT IT WON’T START IN THE MORNING. BUT AFTER THE TEMPERATURE WARMS UP IN LATE MORNING, EARLY AFTERNOON IT STARTS UP AND RUNS JUST FINE. WHAT COULD BE CAUSING THIS PROBLEM?
The first thing to look at is the modern day/electronic version of a choke.
Grab your voltmeter/see this link & let the testing begin.
A faulty coolant temperature sensor might cause this.
One other thing to check for is a cracked distributor or coil.
The Chart you have referenced is non-linear, and therefore has many errors.
Some of the values shown should be in Ohms—not K Ohms, especially when the engine is below 180F!
IT SEEM LIKE AFTER A HOT DAY 85 AND UP, THEN A COOLER NIGHT DOWN TO THE UPPER 50’S THE TRUCK WON’T START I THE MORNINGS, BUT AFTER THE TEMP GOES UP DURING THE DAY IT STARTS RIGHT UP. I HAVE CHECKED ALL OF THE ABOVE, AND ALL SEEM TO BE IN WORKING ORDER, AND CLEAN. DURING THE WINTER THE TRUCK STARTED JUST FINE EVERYDAY. NOTHING LIKE IT HAS BEEN DOING THIS SUMMER. COULD IT BE A MOISTURE PROBLEM OF SOME TYPE? AND WHAT WOULD THIS EFFECT, THAT WOULD CAUSE THE TRUCK NOT TO START?
I’d try changing the distributor cap. A cracked cap can let moisture in and prevent the car from starting. It’s a relatively cheap replacement, too.
Edit: I clearly didn’t see that Mike already said this!