Gary, solder a short brass threaded adaptor on the end of your throttle cable. Then put a ball on the trottle arm and a nylon ball socket on the threaded adaptor. That islolates any metal to metal contact on the throttle linkage.

It is susprising how little mettal to metal contact causes problems. I fount that touching a long screwdriver to the idle mix jet would cause glitching of the throtle and some of the surfaces as well. Not on all planes, but some.

Make sure your antenna doesn't have any tight turns in it. That may agervate the problem.

Don