09 prostar engine fan.

I have a 09 ptrostar. I replaced my fan clutch about 3 year's ago. And i noticed when it engages at low speed its on off on off consistently untill it hits high speed then turns off once it gets to a normal range. It went out on me about 3 weeks ago. But now its engaging randomly and stays on about 99% of the time even though its new and it normal operating range and ac is off. It would go off for maybe 1 to 2 secs randomly and then comes back on. Sometimes it stays off 1 minute then engages again. I had international look at it and they say its working normal but i know its not. My mpg also dropped dramatically.