Guys, I have my own shop and work on quite a few of these , like the other guys said check the intake heater and solenoid, glow plugs, harnesses, glow plug relay. As far as injectors, run a contribution test on your scan tool, sometimes you can catch a bad one on there, most of the time if I question them I pull them and run them on the bench, I have found alot of times they flow high at lower injection pressure-idle/low rpm, think what happens is the pintle leaks fuel by as it wears and you get fuel running in the cyl vs. atomizing it like its supposed to, under the higher ICP pressure 1500 -2000 ish they seem to flow what they are supposed to, due to the higher pressure forcing the pintle down, a new one flows the correct numbers at every pressure, just something I have found, the other, thing is if you smell fuel bad, check the valley of the motor for fuel , the early ones leak fuel from the vacuum switch on the filter base and the lines from the lift pump. The later ones leak from the fuel drain for the filter base or the base itself. feel free to call if you have any questions, 507-533-6674 thanks Terry Stewartvile Truck Service