High rpm... Help

[mang artemio]

Guys i need your help, i have a 1998 galant 4cl automatic. The problem is my idle is at 1200rpm with no aircon and 1000rpm with ac on. It runs well but it consumes more gas and also i noticed my aircon is not turning on and off auomatically.... Need help guys. Thanks in advance

[elnevio]

My first port of call would be to check (or just replace) the coolant temperature sensor. Pretty sure that all petrol Galants have one of these! It sounds like it could be stuck in cold mode, hence the high rpm and poor economy. Not sure if the air con issue is related or just a red herring.