Dhouston: So if I get you right, you DON'T need a rising edge for PULSIN?

I connected 2 PICS together so the 690 for which I want to time a code chunk sends a pulse to the 684 that will record the pulse length and then display the value to an LCD.
Obviously I cannot use PULSIN the way you thought I do

"The disparity between your readings and your expectations is just due to the limits of accuracy using this method."
-> This is not really a problem. Although I'm disapointed by the strange value I get, the method will always be the same so I only want to compare the execution duration of two different chunks of code. I already noticed that the second chunk I'm timing leaves a led on for about 1s which is far beyond the timeout of PULSIN, no wonder it returns a value of 0... This is because I have LCDOUT and WRITE that may take some time to execute.