Volvo: Volvo T4 idle etc, volvo t4, vacuum leaks

Question
1998 T4 Auto, starts ok drives ok but feels like the idle is to low, cleaned the throttle body and iac, in neutral idles at what looks like 750, when engaed in drive it drops to just above the small line above the 0 not syre if that line is 500rpm, but any how the dash and steering wheel shake quite violently, but not to bad in beutral, disconnected the battery for 12 hrs 3 days ago and so far no angine light. replaced the coolant temp sensor and thermostat.occasionaly on a cold start once engine reaches operating temp ie 93o at idle it will hunt from 750 to 1300 for 5 minutes.

Answer
Chris,
Make sure there are not any vacuum leaks. Clean the fuel injectors and put good gas in. Sometimes the motor mounts get so weak they sag and the the motor is touching the frame so you feel all the vibration, worth checking. Did you have fault codes that might have led to aome other fault? Like Constant Idle speed motor, fuel trim, MAF sensor?