Coil maintenance = scrub connectors? Check resistance?
Scrub the connection points under the springs and resistors, remove the springs inside the boots,and clean them up on a wire wheel,or if they're really corroded buy new boots with new springs from somewhere like Rock Auto.
A little maintence on coils and injectors goes along ways to maintaining a vehicle for many years.
As long as the coils are still firing the plugs it's hardly worth checking their resistance but you could if you wanted,here's the specs for checking their resistance.
Ign coil primary resistance 0.6 - 0.9 ohms
Ign coil secondary resistance 6,000 - 9,000 ohms
But there is another simple way to identify a bad coil: Remove the #2 coil and swap it out with another, easily accessible coil. Clear computer trouble codes. Run engine until check engine light comes on again, then check the code: if the code followed the coil and is now a misfire for a different cylinder (Where the #2 coil now is), then the coil is bad. If the misfire stayed in #2, then the coil is ok and you may have a bad spark plug or clogged or bad injector.
Edit: as for testing the fuel injectors: measure resistance. They all should be about the same, if #2 resistance is way different or has no continuity at all, it's bad.
BUT, the injector can also be clogged or the pintle stuck, with the wiring measuring normal values. You can test the injector by disconnecting and reconnecting the plug while the engine is idling. Each time you disconnect or reconnect, you should note the change in idle speed and vibration, etc.... if one injector doesn't seem to make much of a difference when you disconnect or connect it, it's not flowing enough or at all. This assumes the ignition parts have been checked and are good.
In some rare cases, there may be break in injector wiring or a pulse doesn't leave the computer. You can check the injector wire at the injector by backprobing or piercing the wire. One wire should have constant +12V while the other one gets pulsating ground contact from the computer.
