46u is right. Try adding and subtracting variables until you eliminate the fault. In 46u's case, he's suggesting an experiment to see if the failsafe is to blame. Also borrow another radio Tx and Rx to try. Try it with fresh batteries. Make sure all the connections are tight, wire shielding is intact, and that the Rx (Receiver) antenna isn't damaged.

If it works better with another radio set up, then it is probably time for an upgrade.

Do you have the Hyper 8 RTR or Pro? What I'm getting at is what type of radio gear are you using and what is its general condition. Keep a notebook journal when troubleshooting this issue, that way you don't forget all the combinations you've tried during your testing. Always saves me time.

Another simple range test is to have a buddy hold your bug and you slowly walk away from it while continuously blipping the throttle and giving steering inputs. When it stops responding, you'll know what the approximate range of your Tx is. If the furthest point on the track from the driver's stand is greater than this, you know you're going to have issues. Elevation changes throughout the track may also affect signal range/propegation.