Wet ignition causing misfire. Today, since it all dried out, the problem is gone- or is it. Your warranty is expired, so you have a large repair bill at Mr Goodwrench waiting for you to come in and sign, so they can shoot a little WD40 in and wipe off the spark plug wires.
A flashing CEL means IMMINENT DANGER - the truck could catch fire. (You should know this already, but apparently you've never bothered to look in your owner's manual and are not aware of this common knowledge.) Have it TOWED to the nearest dealer or other competent shop.
Some National Auto Parts stores will check your codes and let you know what could be the fix. I like the other two suggestions about looking to see what may have got wet or looking for loose connections. If you get the codes read it will help pin point the components to check.
GL
Is it possible o2 sensores
Get under the hood and check where the water has got to some electrics/electronics or where the force of the water or debris in it has caused some damage underside.
I have a 2000 chevy blazer and I did a full tune up the other day I hit a puddle and my car started running rough and the check engine light is flashin could anyone help
