I have been running my truck in a construction site/office building near my house. Certain spots of the site, my throttle would go back and forth. Could it be the security system that causes that? I got my radio(JR XS3) from eBay last year. So, it was used. I want to know how to determine if it is a problem of the radio or it is interference coming from the building. Any help would be greatly appreciated.

Thanks