Hi all:
It appears that the Pickit2, if left connected to ICSP pins and a PC USB does influence the results by introducing some type of noise to 16F adc sampling
My experience was for 8 x 10 bit ADC samples summed and divided to 11bit accuracy for voltage accuracy to 2 dec. places. The Pickit2 connection created a noise of up to +/- .08V in the result.
Took a while to trace it down , but pulling it off the ICSP immediately stabilized the readings.
Wp100 you misunderstand, the Pickit2 wasn't supplying any power, the circuit was self powered when the errors occurred. It was connected to the ICSP alone. By powering down the circuit I can directly reflash the hexcode from the Pickit2, which only then supplies power.