While running the a/c fan motor on my 3.5 liter intrepid RT with the dash **** in middle position (doesn't seem to do it on low or high) The air speed fluctuates between medium velocity and high velocity for a few seconds at a time and then goes back to normal. There does not seem to be any reason for it, it is very random and occurs every few minutes. I don't have a clue what may be causing it.

 

Test your blower motor resistor.

http://www.freeasestudyguides.com/ac...-resister.html