Cycaza, I had a very similar issue with my car ! I too let the car sit for a couple of weeks ( maybe even 3 weeks ) without driving it and my engine light came on. I called my dealer's repair shop and they told me to drive the car for awhile so that the battery has a chance to recharge itself. The engine light comes on when the battery's charge drops a bit and needs to be driven/recharged. I tried it and it worked for me ! They also told me that if i had refueled and did not have the filler cap screwed on propperly, that the engine light could come on as a result. Something to do with an air pressure sensor of some sort.
Anyway, Hope this helps....

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MgF3
Vrooooom........