Hey gang, kinda stumped here. Now that the weather is turning I'm having hard starts. Truck starts just fine when the weather is warm and after she's warmed up. Cold weather she cranks fine, catches and dies. I've checked the GPS, have 12.6v at the hot side, 11.6 at the switched side, 10.5v at each gp connector and each gp omhs at. .4 and gp are new zd9s. New return line kit. Fuel filter is full of fuel. Not sure where to look. Truck starts right up when plugged in. One battery is one year old, other is about 5 years. Starter motor unknown age. Thinking maybe starter is getting a bit aged and can't spin fast enough?