Ok, I have an 03 F250 6.0 PSD, I have recently noticed a few things in the runability department that have me a little boggled. This is the only deisel I have ever owned.
1) pulling a trailer (2500lbs) up hill the truck begins to surge and constant "grey" smoke. If I go to full throttle, it clears up in a short distance.
2) I have also noticed what seemed like a "back fire" on a couple of occasions
3) over the last 3-4 months I have noticed my coolant recovery tank is down about 1/4.
4) no loss of oil
5) no codes or CEL
6) fuel economy around 14.7
7) if started cold, even in the summer, I can't expect to drive it for at least 15 minutes until it's "warmed up"
8) recently moved to OK from AZ and the last computer update was done in 2003

Any thoughts would be greatly appreciated. I have thought about maybe the EGR being an issue, but there are no codes and I have never had a check engine light.

Thanks for any help you might be.