Ocassional bizarre RPM spike while starting?

[Kara503]

I would just like to jump in and say- I own a 2000 V70 XC that does the exact same thing- It always starts hard (sounds like 1-2 cylinders fire, then nothing, then all catch all in the span of about 2 seconds). About 30% of the time the tach will spike up to 2.5K RPMs. I recently replaced my ECT sensor and it did not fix the problem. Different platform, but hopefully that helps.