[ttmb]

Your Roush motor should have a voltage regulator in the alternator, thus you should bypass (disconnect) the SPF's voltage regulator. My ammeter does the same thing. I just don't worry about it because it's intermittent. If you want to do something about it, there's something on the SCOF tech. site about how to damp it out. Probably caused by the rapid switching of the solid state regulator, I hear. I freaked out the first time I saw it - but there seems to be no adverse effects (so far). Everything's fine after about 5K mi.

Tom