It sounds like one or more struts is failing or the gforce sensor under the driver seat is the issue. With the engine off and the ignition on, if you switch between tour and sport with the button you should hear all four struts switching between hard and soft. When driving in tour there is a medium setting that is used in different conditions depending on breaking, turning, acceleration and road undulation. Depending on how the dash lights flash can tell you different things but the only real solution is to have a mitsubishi mechanic read the error code on the ECS diagnostic port under the driver dash. www.3si.org
has instructions on how to do this and http://stealth316.com/0-frames.htm
has trechnical manuals that help.
The ECS has multiple error codes and can tell you which strut or ecs component is at fault. When a problem is detected the ECS switches to hard mode and starts flashing the tour sport lights until the car is turned off.