The LSN won't raise and lower engine temps unless all you do is idle around. I'd lean the HSN out just a tad to get the temps back up then retune the LSN to get the idle back. Bascally every time you change brand or % nitro fuels you will have to retune also some fuels just don't work well with some engines just like some glow plugs don't work well with some engines either. you may have just found a combo that doesn't agree with this engine.