Misfiring

My 1.8T is misfiring at idle and does not so much when the A/C is turned on.

17705 - Pressure Drop between Turbo and Throttle Valve (check D.V.!)
           P1297 - 35-00 - -
16684 - Random/Multiple Cylinder Misfire Detected
           P0300 - 35-10 - - - Intermittent
16685 - Cylinder 1: Misfire Detected
           P0301 - 35-10 - - - Intermittent
16688 - Cylinder 4: Misfire Detected
           P0304 - 35-10 - - - Intermittent
16686 - Cylinder 2: Misfire Detected
           P0302 - 35-10 - - - Intermittent
17704 - Error in Mapped Cooling System (check Temp-Sensor and Thermostat)
           P1296 - 35-00 - -

Since then I have changed the spark plugs and ignition coil, but that did not remedy the problem. help!