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Q--Many of the drivability problems I have read about in you column sound like a problem that developed in the mid ’80s on vehicles using port fuel injection.
Hesitation and stalling on initial startup when the engine is cold can be caused by deposits on the intake valve. They act as a sponge and deprive the cylinder of the proper air/fuel charge. Once the deposit has absorbed all the fuel it can hold, the engine starts to run properly.
Gasoline was reformulated mid ’80s to help resolve this condition, but depending on how the vehicle is driven the engine may require additional fuel detergents. A few tanks of gas treated with a high-quality fuel system cleaner can usually remove the deposits.
A--Carbon-coated valves used to be a chronic problem. Thanks you for reminding me of it and its solution. If additives don't to the trick, mechanical cleaning may be necessary.