I have a 96 Chevy Caprice 4.3 V8 and I was wondering if I would have to do a crankshaft position sensor relearn when I replace the crankshaft position sensor...

 

Welcome from Florida. I have replaced several of them and did not have to do anything. Replaced a bad one and it started right up and ran good.

 

Yea I changed it and its starting right up, but the code keeps popping back up.. Would you know why?

 

What is the code? Do the wires going to the sensor look to be in good shape?

 

The code is p0336 and p0335.
I have to look at the wires to make sure they are good.

 

You maybe need to look for "the codes behind the codes".
At least in the LS1 family, CKP relearn is inhibited by quite
a few other DTCs. It's also pretty difficult to do the forced learn
(I had maybe 1 in 10 success rate when I was tuning), the
sequence was pretty fussy).

Crank relearn should sort itself in the drive cycle and only
some other problem, or a driving routine that doesn't hit
all the criteria, should make the forced relearn necessary
(provided you're willing to wait).