18f4550 a/d

[starwick]

Hi all.
I have done A/d to with success with 16f877 and16f887 now I have a problem with 18f4550 the value is fluctuating so much even in the high rail I still get values between 1023 and 1018 and in the low rail some times go up to 8. I think it's a TAD problem but I let you guys help me out.
Here is the code(nothing fancy just read and display):

==========================MCU SETUP============================================  
DEFINE OSC 48
Include "modedefs.bas"
'***************************LCD DEFINE******************************* 
DEFINE LCD_DREG PORTD 'LCD data port 
DEFINE LCD_DBIT 0 'LCD data starting bit 0 or 4 
DEFINE LCD_RSREG PORTD 'LCD register select port                      
DEFINE LCD_RSBIT 5 'LCD register select bit , RS=PORTE.2
DEFINE LCD_EREG PORTD 'LCD enable port 
DEFINE LCD_EBIT 7 'LCD enable bit E=portE.0 
DEFINE LCD_RWREG PORTD 'LCD read/write port 
DEFINE LCD_RWBIT 6 'LCD read/write bit R/W=POTRD.1
DEFINE LCD_BITS 4 'LCD bus size 4 or 8 
DEFINE LCD_LINES 4 'Number lines on LCD 
DEFINE LCD_COMMANDUS 2000 'Command delay time in us 
DEFINE LCD_DATAUS 50
'******************************************************************
DEFINE ADC_BITS 10     ' ADCIN resolution  (Bits)
DEFINE ADC_CLOCK 3     ' Work around that sets Vref bits in ADCON1
DEFINE ADC_SAMPLEUS 50 ' ADC sampling time (uSec)


'==========================I/O SETUP============================================


 
TRISD=0
TRISE=0
TRISC=%10000000
TRISA=%11111111
TRISB=0

ADCON1=14
ADCON2=%10000000
 

'================================variables======================================
adcval var word 
TX VAR PORTC.6
RX VAR PORTC.7

'==============================BAUD SETUP=======================================
N96 con 16416 ' Inverted 19200 baud for the lcd rs232  
T192 con 32 '19200 TTL 
T96 CON 84'9600 TTL
T38 CON 6'38K
'==========================I/O SETUP============================================
'======================LCD LINES SETUP==========================================
L1 CON 1 'LINE1
L2 CON $C0'LINE2
L3 CON $94'LINE3
L4 CON $D4'LINE4

CLEAR

'=============================================================================

  
PAUSE 500
loop:
LCDOUT $FE,l1
PAUSE 50
LCDOUT "a/d test" 

 
MAIN:

gosub adc0
lcdout $fe,l2
lcdout "pot:" ,dec adcval,"  "
pause 600
 
GOTO MAIN


'=================================ADC0==========================================
ADC0:
ADCin 0, adcval
pause 50

RETURN            
'==============================================================================

END

can you please help have a 0.1uf between the input and ground of AN0 the power supply is solid do not change.
ground wire from PS to MCU and to analog input.
anything I'm missing.
tried to change
DEFINE ADC_CLOCK 3 to 0 then 2 then 6 with no help.