[OK-944]

I have a hose clamp that's basically a pair of Vice-Grips but with thinner, "soft" (rounded, non-toothed) jaws. Most hardware stores and some auto supply shops should have these.

But if that hose is old it may also be very brittle...which in your case I suspect as you'd said that it is "very stiff." So I'd suggest first getting a 9 volt battery and doing that test before messing with the hose.

Another approach would be to simply remove the intake manifold and replace one or even both hoses underneath it, and also test the air valve and try to fix it if its wonky. While these valves are a bit pricy to replace new...you can either look for a used one - or, if I'm not mistaken, I believe that there is an air valve made for Audi which may work at less cost...but someone else here will know better than I.

If you decide to remove the intake manifold...just make sure to get yourself a set of gaskets for it ahead of time...otherwise you might be tempted to just reuse the old ones if they "look like" they're in good shape.

Finally, removing the intake manifold means that you'll be either needing to at least contort your fuel hoses or I think in your case also disconnect these as in your car they run over the manifold if I'm not mistaken. At any rate...if your fuel hoses are as old as your car, you may discover at this point that its time to replace them.

Even better...if your fuel hoses are as old as your car - take advantage of the fact that you'll be disconnecting them - and go ahead and replace them. Believe me, you'll be glad you did! (A great resource for top quality 944-specific hoses is Len Cummings, who frequents this forum).