I took my 2003 Grand Caravan to have Autozone run a check becuase my "check engine" came on. I've noticed recently that it's not starting up. It'll turn and turn, but not fire on the first turn of the key. I'll let it sit for a second then try again, and sometimes it'll turn over, and sometimes I'll have to try again. I just replaced the battery last week. Any help as to what these codes mean? They are P0351 and P0353. Anyone have this issue? I have about 66K on it. Thanks.

The codes are for your ignition coil primary circuits. P0351 is for coil #1 and P0353 is for coil #3.

I am assuming that when the vehicle doesn't want to start, there is a lack of voltage on the coil primary side. Check the terminals from the PCM to your Coil out on the coil for corrosion first.
It could be the coils, although for two to go at once would be a stretch.
It could also be the PCM.
I am going to lean away from an open or short in the circuit due to the fact that it acts fine once its running.