You will need to take it to a cat dealer. They have a computer linkage that they use to tune and test the EFI system. I have noticed that on really warm days, my EFI does bog a little bit, but at any temperature below about 25 it runs absolutely beautifully thorugh the entire speed range.MacCat said:Just recently purchased a used 98 zr600 efi. Drained the old gas, replaced the spark plugs. Sled is hesitant out of the hole. Do you have to take it to a repair shop to determine if the efi is working correctly?