[fanaudical]

I have two ways to check spark:

#1 - As you indicated - Remove plug, connect to wire, crank motor over and watch for spark.

#2 - Use an inductive timing light, connect to each wire in turn while the motor is idling, and flash the crank pulley. This has the added benefit of giving you an idea of how stable the spark timing is as well as if you're getting erratic spark. Both contribute to poor idle.

One method of checking wire integrity (but be careful with this one): Idle the car at night. Look for sparks. Mist (with a spray bottle) some water near the wires and look again.

Another set of ignition tests: Remove the cap and verify the advance is not sticking. Verify there is no side play in the distributor shaft at the rotor. Lastly, verify there is very little axial play on the rotor shaft.

The reason for the spray pattern test is to verify you really have spray at all points of operation. My car developed an issue where one injector was providing a stream at idle when the other five were producing a spray. They should all spray at the same lift point of the air metering plate.

The spray test / air leak check / pressure tests should all be done and results evaluated as a whole before adjusting / changing anything.