OK, here's the deal: '88 M5 with 84,000 miles. For the fourth time in its life (first time was around 40,000) it ran fine when parked, but after sitting until cold when cranked it just spins over without a pop. The previous three times it went on a rollback to a different dealer each time. Each time it was fine when it came off the rollback. The problem has never been diagnosed. Any ideas, guys?