rift485

i shifted to second to "stop" at a stop sign the other day and i almost stalled. and no it wasnt because i was goign too slow, duh, i think i was still doing like 15, and its never done that before. my friend said it might have been running too rich, then i realized later that he really didnt answer my question. im sure it could be a million things.. has it happened to anyoen before?