2007 Ford Focus Rattling Noise When NOT Pressing Gas Pedal

2007 Ford Focus 4 cyl Automatic 31000 miles

Hello and thanks for your time!

Back in the spring, my car developed an idle speed problem (accelerating automatically in drive). When the weather became warmer, the problem went away. Now the weather is getting cooler. Although the idle speed has not kicked in yet, there is a rattling sound when I am not pressing down on the gas pedal. When I do press on the gas pedal, it goes away after a second at the most.

When I talked to a mechanic back in the spring about the idle speed problem, he sprayed the hoses with starting fluid and so periodically, I would spray the hoses down in hopes of controlling the idle speed problem without ever finding a leak. Are the idle speed and this rattling now related even though they have not occured at the same time?

Thanks for your time!