I have a ecu talk plugged into the consult port while I'm driving around to monitor a few things etc. I'm having problems with initial rough idle and low idle on cold starts only and also voltage fluctuation between 12-15v according to the ecu talk. The voltage spikes also seem to coincide with a slight misfire/brief rough idle. I've recently done a plenum pull but the symptoms may have been present before it. Wondering if it sounds like the alternator is faulty or something else?