Are you using the Helios? If so check to see if the tx module is did not force one of the junction fingers down, and check to see if it does it with another crystal set.You might want to check that you are not running on the same frequency as somebody else. also make sure your tx batteries are fresh and fully charged. If you are using alkalines( Energizers, Duracells....) always have a fresh set on hand, or buy a set of nimh batteries this way the expense of buying batteries is cut down. One more thing double layer the mounting tape for the receiver to the chassis. These are a few things that you might want to check out. I am sure there are others that some other people might have for you to check.