2005 Mule 610 performance issues
 

Mule runs fine for awhile but sometimes when climbing up a grade it will act like it wants to stall. It only does it for about 15 seconds, only on an uphill grade then it will start running fine again. I have been living with this for a few years now and have done the following:
Empty tank and refill
Replace fuel filter
Checked fuel pump per service manual
Removed carburetor and took to motorcycle mechanic who cleaned it, checked pilot, float, etc.
Ran seafoam thru system
Tonight it started doing something different. It would not idle at times.
So now I have idle issues and issues at top speed. I did notice a nick in the insulation on the coil wire and I taped it up. I am wondering if that or a coil issue may be my problem. I don't ride much in water but the mule has been exposed to the elements. So would a bad coil or wire do something like this?
Thanks for any help