Recently I've been having harder starts with my '03 LB7 in colder weather (20* and under). A little background on my truck: '03 Silverado LB7, 110,000 miles, Federal emissions. Injectors were replaced at 74,000 miles when the turbo went out (failed internal oil seal).

In the past a normal cold start (no block heater) down to about 0*, after key on, the glow plug light would go off after about 6-8 seconds and the truck would start with no issues. Indicated voltage would be in the 11-12V range for 30 seconds or less and then jump to 14-15V, with a noticable increase in interior light brightness when the voltage increased. I believe that jump is due to the glow plugs/intake air heater being turned off.

Anyway, in the past few weeks winter has set in here in Wisconsin and I've had a few cold starts in the 10* to 20* range, no block heater, where the truck would start, but run rough for a few seconds and then smooth out. Over the weekend I intentionally parked it outside overnight when it got down to 0* with no block heater. When I tried to start it the next morning, it cranked for a few seconds longer than normal and when it fired up, it bucked hard for a few seconds before the engine smoothed out, like it wasn't hitting on all 8. The other thing I'm noticing now is that when I perform a cold start I don't get the step up in voltage that I used to get. As soon as the engine starts, the volt meter steadily ramps up to 14-15v within a couple seconds.

The truck has not given me an SES light yet and the wait to start light functions as it always has. Based on the research I've done on the forum, this sounds glow plug related to me. I haven't done any testing yet, but I plan to check to see if I'm getting any voltage to the glow plugs at a cold start. I'm suspecting the glow plug controller may be bad, but that's only a guess. Based on what others have experienced, does this sound like the place to start?

Thanks