I know I have a bad one, but I don't know which one it is. Car doesn't hesitate until I get on the gas in the lower RPM region.

Please advise.

 

A cheap and easy method is to unplug one, see if the idle drops, plug it back and proceed to the next one. If the idle doesn't drop, then that plug wire is not working.

 

Two things to check, your wires can screw up either or both ways.

Use an ohm-meter, the Helm book says how many ohms it's supposed to be.

Then if it's OK by the first test, you can wait till after dark, & this works better with the engine cold. Take off the cover over the spark plugs. Start the engine, let it idle, turn off all the lights & look for arcing. You're looking for a blue glow around the wires. If you see it, that wire is 'leaking' the spark out because it's unsulation is breaking down.

 

stick it on your finger and crank the engine :D