Your claim would be better supported by providing an example of his inaccuracy from something that has actually happened, as opposed to something that hasn't happened.
Cordially,
For starters, Rush made the claim in 2008 that McCain was in better shape statistically than the polls were saying. That the MSM was trying to manipulate the voters, etc. He urged people to get out to vote, just in case they were right, but he doubted they were right anyway. (It turned out the polls were not only right, they underestimated the degree to which Obama won.)
And on numberous other occasions, Rush has spoken wildly about how unpopular Obama has become, hated by all, even by most Democrats, and yet, he has stayed over 40% and is now over 50% in many of the new polls. And his job approval is nowin the strong 50% region. Yet Rush is making these risky claims that anybody could easily beat Obama on any given day. (see averages below)
http://www.realclearpolitics.com/epolls/2012/president/president_obama_vs_republican_candidates.html