ZD1511 not achieving full deck RPMs

[Whiskey Tango Farms]

Anyone else having issues with their zero turn not operating at full RPMs.
I already removed the DPF because that was nothing but trouble.
Wife says that if you stop moving you can hear it slowly rise back up to full speed, but then shortly again the blades slow down again.
Any advice would be appreciated.

 

[JasonW]

Does it have a tachometer? That model has an ECU correct? Have you talked with your tuner?