Do you hear a click when you step on the brake? If not, the actuator may be bad. I didn't have this problem, but the one I did have was a worn gear lock shaft (whatever it's called). Basically, I could press the button in but it wasn't pushing the rod far enough to get it past the ridges on the selector mechanism. I ended up gluing a shim on the button.

96 Green Mystique
Zetec
ATX
No mods yet (wife's car but I drive it all the time)

"If you want something done right, do it yourself or use an SAE mechanic you can buy beer for."

Ricers are like the mosquito that buzzes in your ear but you can't kill. They just won't go away.