When I turn it on it will click off than a nin later it will turn back on for a min and it will keep doing this till I just shut it off. Last year it done done the same thing we had someone come out and they said the ducks were blocked so I replaced them it worked fine after that. I went under the house and un hooked it to see if it was blocked but it keeps doing the same thing. Anybody have an idia what could cause this

Your Nordyne furnace is what they call a pulse type furnace. I have the same thing in my home. I called the factory and spoke to them 6 years ago when I moved into my home and they told me that the going on and off was quite normal. In fact that is why it is called a pulse system. No, your ducts are NOT blocked. Whoever told you this had no idea that the system you have was working correctly.