I had this motor that was surging up to 2000 rpms. The good news is I found issue the computer is shot. I tried to have it cleared and programmed but it works and then stops working.Does anyone have a line on a mefi 3 I need to get one but hoping not to pay a arm and leg for it.

Or should I be looking to go to a mefi 4

To minimize variables I'd keep the MEFI 3 if it was me. Others may have more sage advice. Not necessarily a fan of eBay but that might be a start or Bob at MEFI Burn might have some.