2006 f350 cold start slow crank problem help

[Brettjed]

So I just got this truck a month ago it's got 84,000 miles on it. 2006 f350 SRW and no matter what the temperature if the engine is cold the truck slows down in cranking and take 5-8 sec to fire up. But once I've drove it a little and it get warm it fires up just fine. Is there something wrong if so what do I need to do? Batteries and alternator are good had them tested.

2006 f350 6.0 cold start slow crank - YouTube

*Recently done* The batteries in the truck when the video was taken was 1 duralast gold 875cc and a energizer 750cc. So a buddy had a optima red top he wasnt using the was good with 800cc. I put that where the energizer was and im still having the slow crank issues.

Does anybody have a idea that can help me out?

[southend]

Replace both batteries both the same rating, preferably same make, perform ficm check procedure. And get a monitor on that truck.

Sent from my phone that somebody didn't help me get.

[dkrage]

The two 6.0's I have both cranked slowly for a short time prior to a starter fail.

My 05 got a starter replacement last year and the 06 this fall.

Based on your description and claim the batteries tested good, I would bet it is time for a starter motor.