so for whatever reason, the power of Christ, maybe satan, compelled me to get my xr running and do an oil change on it tonight. had to pull start it down a very long hill, on the way back, it starts backfiring and coughing, finally dies, I knew it was low on fuel, so I took the fuel line off just to see if it had fuel, had plenty, kicked and kicked, started, ran for about 20 seconds, died, starts for 10, dies. so after pushing for a while, I decide to hide it in the bushes, walk home, get my isuzu and a trailer, come back and get it. son of a...... now, Im thinking it may have skipped time, 1 tooth it will still run, just not good, or is it electrical? I cleaned the carb the other week, but will start there just to be safe. any ideas are welcome.