My car hasn't been driven in a while but has been started up once a week or so to let the batter charge..somehow the batter went flat yesterday so i charged it over night.

When i put the batter back into the car, and started it, the revs were around 500 and almost stalled for about 1-2 mins..

after 15mins idleing, i increased the rpm to around 2000 and slowly backed off, but the engine didn't stay at normal 600-700 but almost stalled again? wtf

I've never had this problem since i bought the car, so could it be related to changing the battery?

the car is a 94 ed fairmont i6 auto

Drive it around for a little while and the ecu re-learn and all will be fine.

same happend to my ute. cause it's had a few mods couldn't stop at the lights or it would stall ,took bout a week for it to come back

thanks guys, ill give it a try

yeah dont stress if it takes a while... mine took about a week of about an hour a day...

yep. happens everytime, as said above, the the ecu re-learn its stuff and she'll be good as new mate.