I have yet to see a crankset with integral pedals. Sounds more like the bike was assembled poorly by whomever put it together- they neglected to grease the threads when they put the pedals on, and they have rusted themselves to the crankarms. Another Tempo crankset will work fine with an 8 speed setup, but you may be able to find something used on CL, or on closeout from any number of internet retailers that will work just as well.