Engine Exmark Lazer Z starts to stall and then restarts.

I have a 28hp Kohler engine on my Exmark Lazer Z EFI. I will be driving back to my car and the machine will start to stall and acts like its losing power and then just when its about to completely stall the engine kicks back on. I have replaced the fuel filter and that did nothing. I have upgraded from 87 to 93 fuel. It doesn't seem to matter if the pto is on or off, the machine still acts like it wants to stall.