So I just bought an 05' S40 about a month ago. It rode fine for the first few weeks, then one day last week it just started to sputter, majorly backfire, and then die and wouldn't restart. I would leave it alone for about 15 mins, then start it up again. It would go about a quarter mile before doing the same thing.
Even though it was half full on gas, I filled it up with gas and that seemed to get me the last few miles home. So I thought the problem was that it was just low on gas. So I started to take it to work the next day, full on gas, and it did the same thing again, it would go about quarter mile, then start sputtering/backfiring and then die.
Any ideas where to start looking for the problem?