OK this is a weird one...

I have a EF yak 74" with a Brillelli 36GT. Have about 1.5 gallons through it...so about 15-20 flights. Yesterday I noticed something really weird as I was coming out of a blender. It sounded like my engine was reving up and down. I was able to land no prob and killed the engine at the end of rollout. I checked over the plane and saw nothing loose. I am running the Spektrum AR7000 and a Hitec MG225 servo on throttle. There seemed to be nothing wrong as I moved all my control surfaces and the throttle. So I started the engine and it was running rough. But actually I found the throttle servo "glitching" through its idle to half throttle range. I had some control over the throttle but it continued to twitch. There were no loose wires. I re-binded the Spektrum and did a range check..still had the problem. I have never had a problem before. I don't think it is RF interference since it just started and I have so much flight time on it with no problems at all. Any suggestions as to the most effecient and cost effective way to diagnose and treat this problem?

Thanks mark