I herd johnyy knoxville was sucking off ryan wen he crashed ? are these rumours true?

You don't state WHERE you heard this ridiculous rumour. Sounds like an example of bizarre gallows humour. But considering that Ryan Dunn's Porsche exploded in flames and killed an (as yet) unidentified passenger and Johnny Knoxville attended the funeral UNHARMED, it appears extremely unlikely. Even unlikely that Johnny Knoxville was IN the vehicle at the time of the crash.