yet another post about the subject....my 94 st was idling at 1600 rpm and the temperature is stuck at cold as can be... what seems to be my problem thermostat and iac?

Sounds to me like the thermostat for sure. I had the same problem with mine. I could drive around for 45 minutes and still not have any heat. And let me tell you, when it's 15 degrees outside, that sucks! I would definitely look into your thermostat. It cost me $8 to fix mine and was well worth it. Especially with winter here. So even if that isn't your problem, you aren't out very much money.

I think you're looking at one problem you need to fix first, the temp issue. If you're car always thinks it's cold then the idle is going to stay high. Fix that first then see if the idle goes back to normal.

what about the cts? coolant teperature sensor....

unplug the sensor and test the resistance. don't replace it unless you have to. the CTS is not a part subject to wear and tear. replace the thermostat, even if thats not your current issue, you don't have to worry about it for a long time. there are actually two or three coolant temp sensors on an ST. one for the ecu and one for your gauge. one is on the thermostat housing under the throttle and the other is behind the water pump, on the passenger side, under the intake mani. it will be on a pipe that leads to the water pump