Over the past couple weeks, happening several times a week, when turning on the ignition, I get only a single click sound coming from around the starter. Backing off and then back on with the key, it usually does this again. As more time goes on, it seems to take more attempts, 3 or 4 now, before the starter turns and the engine cranks up.

This phenomenon only seems to happen after the car is allowed to sit - first thing in the morning or, following a several hour sit in a parking lot. After it does start, it will give a strong start time after time, as if nothing is wrong. Sometimes, it starts right up cold without a hitch.

It does have a fairly recent battery which was replaced around the first of the year.

Took the car to an auto parts store, Adance Auto parts - who hooked up diagnostics via the pc connect terminal; according to them, battery is 'good' however remember that I had to drive down to the store obviously after the engine had already been started. Their printout also said the 'Starter Test' showed a drop from 13 down to 9 (11.32 amps) during the crank. According to the rep, this number should stay around '12'.

Questions:
- Are these auto parts tests generally very reliable?

- Does this sound like the selonoid, not causing the starter to receive proper current?

- Does it sound like a battery? Which I will be disconnecting and taking over to the parts store where it was bought, so they can hopefully test it (without charging) for cranking amps.

Right now I can't tell if the battery is not holding a charge (or a possible leak somewhere?) or its being caused by the starter/selenoid. I'm guessing that it isn't anything else like the ignition or the starter-to-battery cable given the somewhat predictable timing of it. On a past Acura, I did come across 'vapor lock' however when the gas was allowed to get way too low in the tank. The above is happening regardless of how much gas.