Does that mean that I need to have a 10ms pause after the write instruction to make it wqork correctly?

Ill do some research on what you mean by PULSIN 'swing'.

For this part, I want to run an engine at a certain rpm and then do a PULSIN to get the time between triggers. When I press a button, I want to save that value to compare later. Then it continuosly does PULSIN and compares the saved value with the new one, if its a smaller value, then the rpm is higher and I turn on a light. If the value is larger then the rpm is slower and the light goes off. My problem SEEMS to be that it doesnt save the value correctly or not at all when power is removed. So even if not real accurate, the value should change.

The rewrite was put in to make sure the write happened do to it not saving correctly. I guess this is not the case so it can be removed.