i don't know whta's going on but this started after i changed my intake manifol.. i got the RPM performer II a new TB and EGR from edelbrock... now before when the engine was cold the rpms used to fluctuate sometimes even stall, on cold weathers.... not it wors fine but i have another problem.. don't matter if it's colld or hot, when i stop at a light or let ut idel stais around 900-1000k rpms then after maybe 5 sec goes down to 750-800 which it was set to idle... rigt after i got it out of the shop i wanted to idle around 800.. and it does but aftre it's in the 1000k rpms range and then goes down...