I have got a problem, I have a '03 Grand Caravan with the 3.3 engine and it is giving a code of p0340 which is the cam position sensor, the only time I get it is at start up when it cranks for a few seconds(3 or 4). It doesn't happen every time, some times it starts great.
I was wondering where the cam position sensor is located and what the easiest way to replace it would be, other than having a mechanic do it?

 

Welcome to DF
The cam sensor is bolted into the front timing cover, near the intake manifold. If the code comes back, You could have a bad flex plate.

 

It has Come up twice in the last week . How could I check to see if the flex plate is bad? Where is the flex plate and how hard is it to replace?

 

I would replacing the sensor first, because to inspect the flex plate. You need to remove the transmission.