I'm sorry for the massive bump

but this afternoon I was driving the F08 around Aston and I experianced the same thing.. I was just using the Race_S setup but with 25% air intake restriction. The car didn't want to shift up from 4th anymore..
As posts above say it's a set-up issue, but a standard unmodified Race_S setup also does this so that makes me think it's not setup specific. Wich would make it some kind of bug?
