Help 97 Tahoe Check Engine Light On

My Tahoe Has A Check Engine Light On... The Code It Read Was
P1345 ....camshaft To Crank Shaft Position Correction Fault..
What Does This Mean.... Is It Something Simply I Can Fix Or Is It Something I Have To Take To Mechanic To Fix... Thanks For Helping

The dist is slightly out of phase with the crank sensor, the cam sensor is in the dist, this is why. It must be put on a scanner and the cam synch signal set to as close to 0 as possible.

Has the dist been removed or moved?
Any other codes?
Any repair or service history.
Mileage on tune up stuff?

tune-up has been preformed everytime we go and come back from our long trip 1 1/2 months to Texas. I do put aftermarket distributor cap and rotor. might this be the problem. My truck has 134 K miles.

Aftermarket cap and rotor is not good.
Did the code pop up right after cap and rotor replaced/
As Maxwedge said you will need a good engine capable scanner to check/set the dist camhaft retard setting.
I would suggest a new AC delco cap and rotor.
And getting it on a good scanner and set dist as close to 0 degrees - or + as you can get it.
Good luck and let us know how it goes.
MT