A quad jump is a movement technique that can be used to gain more height than other jumping methods. It can only be performed in Jak and Daxter: The Precursor Legacy with yellow eco. The method to perform a quad jump is to first press and hold cross twice to double jump, followed by pressing square to shoot yellow eco, and finally pressing circle to spin.
It is also possible to add an extra jump by using the jump animation from picking up eco and then performing a quad jump.
It is not currently known how or by whom this technique was discovered.