I have already replaced MAP sensor and installed a 2nd TP sensor. Getting code of P0068 again.

Question

Truck stalls and idle is inconsistent up and down.

Answer 1

P0068 MAP / Throttle position correlation - vacum leak detected

The main cause for this code is vacuum leak especially at the intake or brake booster area if, there is none, and because you have already replaced the TPS  and the MAP, check the its ground connection, there is a BLK/BL this is the sensor ground whih gives ground to the TPS , MAP, Engine coolant temperature and CKP sensor.