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When the Check Engine light is blinking, this is the sign for a P0300-Random Cylinder Misfire. It's a fairly "geneeral" code that basically means, the on-board computer sees a misfire, but hasn't quite pin-pointed where the misfire is, or what is causing it (see possible causes below). Your best bet at this point is going to be to get the "p-codes" read from the on-board computer, and see if there is anything stored besides the P0300. Once you have these codes you can more accurately and efficient diagnose the problem, and narrow down the culprit. You can have these p-codes read for Free at any local "big chain" parts store (ie. AutoZone, PepBoys, etc)