Trying to track down some interference. With the car on and transmitter off the servos go crazy. Flip on the transmitter everything is good but after driving it for awhile, say 4 mins into a 6 min race the car starts acting up. I changed out receiver and transmitter. Any ideas? Bad ESC? Motor has internal capacitors but I can solder more on. It is my daughters TC3 stock touring car.

For the first part just always turn the transmitter on first. Which should always be standard procedure.

The second part sounds like tired batteries, is the car’s performance also dropping off at the 4 minute mark? Nimh batteries?

Hard to tell. I plan to take the car out and run it under controlled conditions. Try and get a better feel.