Lift pump started leaking the other day so I replaced it with a Carter assuming they all suck now but thats the best of the worst. Bled all the injector lines I could reach easily all at once till they wept diesel. (this is a factory turbo so two lines weren't accessible) retightened lines and truck started right away. 2 days later and I'm experiencing hard starts when cold. First crank, it starts for one revolution then dies. Assuming its using the fuel between lift pump and HP pump. Then it requires 30 seconds of cranking till it starts. Does this sound like the line from tank to lift pump is empty? Like the Carter I bought has bad check valve? Do lift pumps have flow back prevention? I've been reading the whole forum and feel like someone who has a mild cough, reads the internet, and is now convinced they have ebola. Like, this could be air intrusion too I guess. I do wonder why yall diagnose that for hard starts but normal running when warm. Does air intrusion not matter as much when warm?