In the last month the MPV has become increassingly hard to start. It will stay running as long as you gun engine. At first it would settle down quickly and then normal idle but as days have passed it takes longer running time to achieve regular idle speed. As long as I hold foot on accelerator it will drive fine. Extra cold days it seems to take longer to get engine to achieve normal idle. Am looking at replacing IAC valve and wondering if any think this will help? Is this hard to do?