Where are they at? The old lady's 2000 4 door is throwing code po335. I've been told it's behind the flexplate, behind the crank pulley and on the back of the head. I'd just buy a sensor and look for it but I don't feel like pulling the tranny to replace it if that's where it is.

You've got the location down (back of the engine, block area and pull the engine to replace), but they rarely (if ever) fail.   In all likelihood it's a bad wiring plug / connection or a chafed (shorted / parted) wire. Investigate that closely before you suspect the sensor proper.

 P0335 CKP Sensor Circuit Malfunction   

Thanks... Any idea what the plug looks like/how many wires go to it or where the plug is located?

Can't help you there or I would. I've got the 2.5 V-6 and it's in a totally different area. I'll bet someone else will chime in though that has a 2.0.   

wow never thought I would be able to speak on this....BUT

I just bought some cores from the Head Honcho here and 1 of them was a 2.0

I will go out to the garage and get the sensor and take some pics. I have the block (it was trashed) but the sensor was there, I'll get a pic of the block too so you can see where its at!!

Zack