I already tried the combustion chamber cleaner hoping it would solve the mild vibration at idle issue but sadly it didn't solve.

I tried these:

- changed injectors
- changed cap and rotor
- tightened all vacuum connections
- cleaned combustion chamber

they don't solve my problem.

A guy on this forum commented that rough idle is by nature to CIS systems. (http://www.peachparts.com/shopforum/showthread.php?t=85476). I mostly agree with him. What do you all think?