I did switch over from primary external clock to internal clock and it works better now!
But if the PIC sleeps more then 1 second i get into trouble.
So guess the PIC cannot sleep more then 1 second to get proper result?
Because the interrupt routine is build to do a interrupt every second. And an TMR1 interrupt would not execute if the PIC is in sleep mode, right? Even if i have secondary clock source for TIMER1?