Hi Stuart, on the weekend my IS220d 2006 also revved uncontrollably. Thankfully I was in neutral, as I was changing gears, so did not accelerate uncontrollably. I called the RAC, their best guess was turbo fail as a lot of oil was leaking, and they towed me to the Lexus workshop.
The Lexus mechanic just called and stated they cannot see any issues, save oil replacement and new battery (not sure if this is related or just timely), and further the diagnostics showed up blank. Reading your thread I can see the damage the revving caused (seized crank), however, did you determine the cause of the uncontrollable revving?
I fear it will happen again, this time in gear and I too will accelerate. Perhaps it was a freak occurence but not ideal. Any views would be kindly appreciated.
