Just saying because my friend ran into this problem with his 02 Z06 that is superchaged and running E85. This crap was all over his injectors until they were almost clogged as well as caked all over the intake valves. A good amount of soaking in Seafoam cleared the injectors, but still trying to figure out how to clean the intake valves without pulling the heads etc. Some say that running a tank of regular gas will clear up the issue, but we have to re-tune for the 91 octance we have here and there is still snow on the ground so I cannot confirm that this practice is applicable.