engine mounts get bad enough they can break loose and cause massive prob. the engine mounts are what hold your engine to the frame. if they are sketchy you may have to bite the bullet and have them replaced.
however engine mounts really have nothing to do with how the engine runs. low idle could mean so many things(needs tune up, prob. with fuel system, prob. with air intake or exhaust system, etc.). best to get diagnostic run to see whats going on.
I already replaces the new fuel pump,fuel filter, EGR, EGR vacuum, idle sensor, and clean throttle body but it didn't seem any helped. Is it low idle and the car die sometime, if the fuel pressure is bad? any idea? Thank!
you have taken care of sensors now look to components. use ethanol treatment in fuel system, this will clean entire fuel system of ethanol resins that build up through time. this build up can impede fuel delivery.
use oil stabilizer in engine to recondition seals and cylinders. this will boost compression.
have cat. conv. looked at to see if it's getting clogged.
do a fuel pressure test to insure new fuel pump is functioning properly.
consider upgrading air filter to high flow design such as a K&N filter(this filter type is re-usable, requires clean once a year. may last up to ten yrs. plus). this will allow your engine to breath a lot easier.
review when last tuned. consider upgrading spark plugs to premium type and ignition cables to performance type(accel's are pretty good and more cost effective than OEM replacements).