If you're still using the old 27mgrtz controller & rx, ditch it. The one with the long antenna you pull out. A cheap 2.4 is better that one of those. I had a T-Maxx runaway with one of those. Cost $90 to repair the damage lesson learned. I just traded a Ofna nitro to my son this weekend, it had the Ofna am setup. It would glitch so badly, just touching the glow ignitor against the engine it would freak. He put his newer 2.4 Spektrum on it, glitchs gone.

Replace the old obsolete TX and RX and recalibrate.