Cathode: You may want to check your optimized TB and make sure that there in no leakage around the butterfly. If the edges of the butterfly or the diamater of the bore where the butterfly closes change, you'll get extra air seeping past the closed throttle plate and a higher idle. Another source may be that the throttle shaft is binding and not closing all the way. Cleaning the shaft or adding a throttle return spring may do the trick for you.
Might want to double check for other hose leaks/cracks while you're at it.
