Hi !! A question here !
 

Ok im having a problem with my galant 2004 ...

Ok my battery went dead so i change it ...but after that the car
wouldnt start ...the front panel went off ..so i called an electromechanic
and after a few steps by the phone he told me that was a conector and he was right ..!
The battery ground cables had corrsion ( like green powder ) and i had to clean it as i could because they are too short !! ...my plan was to cut the cable but i couldnt because
it is too short like i said ....both cables ...
Ok after that the car started very fast and with more power ..the problem is that after that the car sometimes shake a little on idle and when it does i see that the RPM lowers down to 500 or so....then the car it turn up again and stop the vibration .....its sometimes that this happens ....and never happened before the battery change ...i red in someplace that maybe the ECU take sometime to relearn but i think its not my case because of the time that this happened....this was about a week ago ....

What this could be ...??

Sorry for my english !!! :-( and thanks !

ahhh. The joys of modern technology.
you may need to remap/flash the ecu. Sometimes this can be done with a paperclip, others, requires a professional with a gadget.
Google is your friend.
Hunting at idle would normally indicate out of tune, or vacuum leaks. Since the battery is the only thing thats (presumably) changed, sounds like tuning issue.

Hi and thanks !!
Can you post a link ? becasue ive tried a search with no luck !! :(