When my CT4S hits higher RPMs, the servos start to glitch. And, they don't just glitch a little, they jerk all around. All radio equipment is in good condition, battery charged, etc. Could the interference be caused by metal-on-metal inside the chassis somewhere? I'm glad I found this out before I tried to top the speed out on this thing.

Things I've tried...
Different servos
Completely different radio system(stock AM and Futaba FM).
Different battery(4.8 and 6.0v)
Holding the reciever above the aluminum upper deck to see if the metal deck as transmitting interference to reciever

check to make sure that you have the correct plugs in the right place on the receiver. fun1 is for servo, fun2 is for throttle. also make sure that there is no play with the servo saver and the tires are properly aligned straight.