I have a 7.3 with approx 223,000 miles on it.
I have replaced the glow plugs, fuel filter, air filter, glow plug relay, optima red top batteries (2)
When cold I always have to have the thing plugged in and after approx 7-8 hours of sitting outside it will try to run but chugs as though its not getting something.
Oil level is good and I plan to replace with T6. I will then do a top end oil replacement in the HPOP reservoir.
If I follow a sequence of turning the key on and waiting until all is done running then doing it again 2 more times it will start most of the time.
Any suggestions besides the dreaded injector replacement?