Has the car been scanned to see why the check engine light is on? the low temperature makes me think its a thermostst stuck open pre venting the engine from reaching normal operating temperature. You may also want to check for vacuum leaks which will give you the high idle you are describing
If memory serves me correct the computer in that car is under the dash above the glove compartment. I do not think this acr needs a computer.
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ASE Certified Technician
ASE certified technician; former ASE master Technician; Automotive instructor