Turbo/Power issue??

[OneRoper71]

I have an 03 250 2wd all stock.I just had to have the gaskets around the oil cooler replaced it was pouring oil everywhere. I got the truck back on friday and the nechanic told me that since the truck had been there for 2 weeks they had the batteries unhooked. he then told me it would take a while for the computer to recompensate and it would be fine soon as I put a little time on it.
Ive drove the ruck a bunch and ran it up to 80 on the interstate etc. Problem I am having and finally noticed it today trying to pull my horse trailer is when you step hard on the fuel and it kicks down,it revs ups like normal and tries to pull but its just lagging and going nowhere but revving. I also heard what sounds like an abnormal air hiss around the turbo that may have been there before the work.I am planning on taking the truck back but was wondering if it was what the guy said it was and if that was true if it just needed more time.
other than that it runs out fine and everything just has NO fast get up and go.