alrighit i stole this from another post because this is the exact problem i have.
Yes, a big mistake. I had a set where the cores had 2 in it that were flat out bad, they would piss oil straight across the poppet. The customer bought a set from Pensecola and sent the cores in. The set from Pensacola was just about as bad as the original set, as it would only hit on a few cylinders when cranking it. When it finally did start it would only be running on about 4 cylinders and as it warmed up it would start picking up cylinders.
2000 f250 ECSB Dually 4.10s 305/70/16, 4x4 7.3 zf6 200k miles
Php hydra chip PHP tuned! 4" exhaust, stock turbo(ww2, turbomaster wastage actuator, gutted ebpv), FRX, 160/30 sticks SB 1939-CB single clutch, home brew water setup for when i'm pulling hay through the mountains.