Monday, May 29th 2006, 7:40 pm:

I'm driving home from Panda Express (after dropping tim off at the airport so I had to find food on my own). A little yellow light reading "Service Engine Soon" illuminates in the dash. I think: "Hmm, that's odd, nothing seems wrong with the car, its driving fine and sounding fine."

Tuesday, May 30th 2006, 7:49 am:

I drive to work. The light is still on.

Tuesday, May 30th 2006, 12:05 pm:

I read some websites that indicate that the problem may be as simple as the gas cap, or may be much more complicated. Most sites recommend disconnecting the battery for 10-15 minutes to "reset" the computer, and check to see if the light comes on again. More expensive fixes require $85 to read the error codes from the computer. I think "Why in the world does it cost $85, sheesh... it should only take 5 minutes if that, and the equipment can't be *that* expensive..."

Tuesday, May 30th 2006, 4:52 pm:

Before leaving work, I remove and replace the gas cap. There is a mild rush of air as the gas cap is removed - nothing out of the ordinary. I drove home, and still nothing out of the ordinary - except the illuminated warning light.

Tuesday, May 30th 2006, 5:17 pm:

Arriving home, I pull out the handy pliers, pop the hood and disconnect the positive terminal of the battery. After the battery is disconnected, I spot something odd on the engine block. Or rather, I spot something lacking... the oil cap. It's not there. Mr. brain thinks "If I were a car's computer and I had a way of detecting the oil cap missing, I'd probably put up a warning of some kinds."

Tuesday, May 30th 2006, 5:21 pm:

Report the news to Al, as I'm sure its something worthy of him hearing. Investigating, I determine that I last changed the oil in February, which was the last time I even opened the hood. Call the Nissan dealer, order a new cap (they don't stock them). It'll be a few days before it arrives. Text Tim, ask if its ok for me to drive his car until I can get mine fixed.

Wednesday, May 31th 2006, 9:38 am:

While talking to some people at work, I recall hearing a noise while driving to Panda Express. A sound like a rock kicking up and hitting the front fender. Could this have been the oil cap breaking off and hitting the hood? Perhaps.

Thursday, May 31th 2006, 1:13 pm:

Nissan calls, the part is in.

Thursday, May 31th 2006, 4:57 pm:

Heading home, stop to pickup oil at Wally World, and the new cap and some filters at Nissan.

Thursday, May 31th 2006, 7:00 pm:

Change the oil, put on the new cap. Start the car... drive around the block, no illuminated warning lights! Success!

Per Al's recommendation, I'll be changing the oil again in a few hundred miles to clean out any debris that got into the system with the cap off. How did the cap come off? Or, did I forget to put it on in February? Still a mystery. I did however check, and very little oil splatters out with the cap removed, even with the engine revved... so either seems to be a possibility.