Electrical Problem, F250 SD

I have a 2003 F250 SD, V10. Occasionally, when I start the truck, it barely rolls over, like a dead battery, then starts. The gauges spike all the way over for a few seconds, then fall to zero for a few secs, and then read properly. The tripometer also resets to zero every time. Battery and alternator test ok. Have had this problem since I jump started my buddies Diesel on a cold morning- which took a ton of cranking. Checked the batt. terminals, cables, and all the ground points I could find and all look ok. Any ideas?