is it the glow plugs or intake heater
My truck has been very difficult to start all winter long. Much below 20 degrees it has to crank for a while before it fires, and it has not started at all when it less than 0. I originally thought it was because I had mostly summer fuel in the tank because I didn't drive it much after September, my first refuel was late in December. After driving it extra and even putting in some kerosene I am still having the same issue. So I noticed the other day I turn it on the wait to start light comes on and the voltage is around 11 volts. It used to be after I started it the volts would stay low for 10-15 seconds maybe even a minute after it was running. Now the volts come up to normal, about 14.5, right away after it starts. So I got to thinking one of the 2, either the glow plugs or the intake heater has quit on me. I'm hoping someone can diagnose which one it could be from the info I've provided. I've read what I can about the GP and intake heater relays, and since they appear to be pretty expensive and it's starting to be spring finally and the truck seems to start OK above 20 degrees and I am getting a new truck this summer, I probably will just ignore it. But I'd still like to know...Thanks
Got Big Truck 2001 Chevy/Duramax/4X4/6 speed/crew cab/long box