The 6.0's are a crap shoot. Some are very good. Others not so much. When they do break down they are VERY expensive to fix. 05 and 06 were the best years for them.
Do NOT chip a 6.0. They can make silly power chipped but they will have problems if you chip them and you will be looking at replacing the head gaskets and going to arp head studs. I know this from experience and it is not a cheap fix.
Take the truck to an independent mechanic and have a leak down test done on it. The head gaskets are a really common issue on this motor due to the torque to yield head bolts.
Do NOT chip a 6.0. They can make silly power chipped but they will have problems if you chip them and you will be looking at replacing the head gaskets and going to arp head studs. I know this from experience and it is not a cheap fix.
Take the truck to an independent mechanic and have a leak down test done on it. The head gaskets are a really common issue on this motor due to the torque to yield head bolts.