Hello I have been into nitro R/C for 35 years or so. My first fail safe radio was a JR Radio Alpina PCM and have always had fail safe radios thereafter even the Spektrum radios.
I never had any issues with any radio what so ever as far as the fail safe failing.

I do know how fail safe works, if the RX looses the signal from TX the fail safe will engage and return the throttle to idle and stop all steering input.

May I ask why my 4tec 3.3 when it hits a bump the fail safe engages. When this happens the engine goes to idle and the steering locks as it should but if I switch off the TX and turn it back on the fail safe will dis-engage and I have control of the car again.

I never ever seen this happen with any other radio.

RX batteries are 2500mhi and charged.
TX batteries are 1200mhi and charged.
RX is not wet as I run it in a balloon. "I come from nitro marine"
Servos are plugged in.
I am not running the car to far away or even close to being out of range.
I am not running with other people.
The RX antenna is fully extended.

Is this a known issue with the TQi radio? I never ran a stock rtr radio.

I am wondering if the tuned pipe right under the radio box is the culprit "radio Interference from the tuned pipe" as I have been into nitro for 30-35 years and know how to tune a pipe, I am wondering if the tuned pipes pinging sound could be interfering with the RX? Because if I turn off the TX and turn it back on it resets the fail safe (I don't have to turn off the RX just the TX) so I don't think it is a TX problem because the fail safe is in the RX as it detects when signal is lost. usually if the TX is the problem and the signal out is bad simply turning the TX off and on usually wont fix it, but I don't know because I am not to familiar with the Traxxas TQi and their fail safe set up. I really don't need the link up function so I am thinking just getting a Spektrum radio but would like to keep the TQi because I already have.

Any help would be awesome, I never had a fail safe engage simply going over a bump so I am dumbfounded.