I have a new on30 forney that runs smoothly. However, when I stop it and restart it (to change directions or just to continue on) it often won't budge. The light often comes on, which to me means it's getting electricity. A slight budge and it starts up. At times, the light won't come on when I reapply power, but again a slight budge and it restarts. I know it's not the track as I have a second forney that doesn't have this problem. Any ideas?