2002 93 brake issues
 

I'm having some issues with my 2003 93. The brake pedal goes to the floor but comes right back when pushed again and the brakes work fine. This happens once and a while. I can drive it for days without issue. I had new rear brakes put on, tried disconnecting the abs-to rule out the booster- reconnected the abs. Drove the car multiple time- brakes work fine. No leaks, no cracked hoses, no dragging calipers. No warning lights. Nothing. I welcome any help yu might be able to render. Thanks. Jim