Ted

I had the same problem with a touch pad. The streaking in my case was pen pressure related. I added a "Pen Down" function that would only let the pad draw if the pressure was greater than a preset value. Here is the code in C
Code:
int PenDwn (void)
{
		OpenADC(ADC_FOSC_64 & ADC_RIGHT_JUST & ADC_8_TAD,
		ADC_CH0 & ADC_INT_OFF & ADC_REF_VDD_VSS, 11);
		TS_Y1_Output;  //make Y Pins outputs
		TS_Y2_Output;
		TS_X1_Input;  //make X plates inputs
		TS_X2_Input;
		TS_Y1_ON;	//energize Y plates
		TS_Y2_ON;
		SetChanADC(ADC_CH0); //select voltage channel
		Delay10TCYx(200);
		ConvertADC();   //read ACD
		while( BusyADC());		
		PenPressure=(1023 & ReadADC())>>2;
		if (PenPressure > 210)
			{
			return (TRUE);  //pen pressure exceeded threshold
			}
			else
			{
			return (FALSE);
			}
}
Basically energize both plates and read the output from the pad.

It worked well for me

Dave