I sell and make parts for ignition every day and the one most common call I get for support is when I sell a G62 electronic conversion.
Customer says ignition works great but the servos on there plane go crazy, I tell the how to install the plug cap.
Some will call back and tell me it solved the problems and other I never hear back from.
Install your plug cap down to just where it touches the hex on the spark plug and crank the engine and see what happens.
Milton