just one day when it it warm, rule out that it isnt the cold. my truck did the same thing, eneded up being an injector returning to much fuel and the truck had to turn over twice as long to build up proper rail pressure to get it running. did the same excat thing as your, had to hold it till it stopped turning over atleast 4 to 5 times
2003 duramax silver birch...ccsb
finally bought it from my dad and had it painted a charcoal color, new injectors, h2 rims, 285-70-17 fierce attitudes, raptor 150, cat filter adapter, edge cs with probe..... 210,000 and climbing
dont know which way to go with it for future
efi live tuning- Kory willis......awesome.