Been battling this for about 2 years. Finally decided to get some good clamps and get my power/ground from the battery. I also have pin #5 grounded to the battery as well. There is a large amount of lag timing in Hptuners vs my meter. Also the readings in hp tuners are just too erratic. Help! Once thing I did notice is when logging raw voltage I'm at 1.377 Volts at 14.7 and 1.309 at 12.0.