I recently bought a used 1/8th car containing two identical Dash ST702 by arrowmax servos. I also bought a new Futaba R203GF receiver from a retailer. On only the throttle channel, and blank model on my radio (Futaba 3PV) connected will result in the servo twitching in its neutral position, the servo connected to steering is normal. I tried this on a known working servo and it had the same result. The servo in the throttle channel does not twitch however when I put it on my 1/10th scale nitro cars model, but I cant think of a setting that would cause this. I also tested this with 3 other new receivers and had the same result (two other r203gf and a r204f-e).

I have had twitching in the past with low transmitter voltage getting into low 4V, with replaced batteries (3 out of 4 replaced) I get a 5.9V reading. Which has no low voltage feedback on my other cars.

Any ideas?

Is there a transponder close to the receiver?

If you swap the channels so the steering servo is in the throttle channel and vice versa, does the problem follow the servo or the channel?

I'd do that! Also recalibrate you ESC. What is does replace the servo.

There is a transponder 5 inches away not powered. Switching same servo to steering has no problem, its only the throttle channel with any reciever, I’m thinking transmitter issue.

No ESC as its a nitro car.

If it's a transmitter issue I'd expect a different servo to also twitch. Did putting the steering servo on the throttle channel lead to twitching?

Yes lead to twitching putting steering servo on throttle. The interesting part to my is my 1:10 nitro module with throttle adjusted did not twitch when connected, all other models don’t have any throttle settings adjusted except that one model, all other models twitch.

Might be a bad throttle potentiometer.