New to the forum so maybe there is a thread. I have a Stargazer 8.0 on my 95 Nautique, GT40 using no magnet timing. Have calibrated, tried tach inversion, different values for Kx and results are similar. In GPS slalom mode, boat always enters hot no matter how slow I push throttle to engage (about 31-32 mph), then throttle jumps up and down for first half of course, finally ends up slow (28 - 29 mph) with a fairly accurate time. Runs fine in Classic Slalom mode which at my skiing level is not an issue. Just curious as to whether this is a common problem or if there is a fix. Wondering if it is a noisy GPS speed indication?