Yes, I have the same problem on my 2001 996. Dealer replaced the tach twice, computer once, checked grounds and a few other things. Then they were informed by Ducati that it is a common problem to the superbikes, they did not have a fix, and told me in an email (Ducati USA) that they don't feel there is anything else they need to do about it. Mine jumps and/or sticks as much as 500rpm's in the 2000 to 4000 range, and has been doing it since new. Nice, huh?