Gem car won't get to full speed

My gem car won’t get to full speed it is maxed out at about 13- 15 mph. I can come to a complete stop and start again and sometimes it will get up to about 23 and then lower back down while I still have the throttle all the way depressed. It is not showing any error code

Make sure your not in turf mode.

Monitor the battery voltage when the problem occurs and see if it is dropping too low. As mentioned, make sure that the HI/LOW./REV switch is working properly.

Did you ever find a solution? I have the same problem…

That would happen to me and then I’d get the turtle. Would top off batteries (lead acid) and perform individual charges to get them up to 12v and then put on 72v charger over night. Would usually cure it but eventually, I had to replace the batteries as they were 5 years old.