05 Titan running like crap! Need help!

Need Help! IPDM? Cats? Or Fuel Pump???

I have a 2005 Nissan Titan with 105,000. A few weeks ago I was towing my camper and the truck started running ruff. Scanned code and p0174 came up. Ran sea foam in the gas and it started running great again and the SES light went off. A week later towing the camper again going up hill in 3rd gear at about 4000 rpm and all of a sudden the truck goes to crap. Can go over 25 mph SES light on and flashing. Towed 100 home. Codes p0300, p1168, p1051 came up. Replaced the F/A sensor 1 on bank 2, cleared the codes. Nothing changed, still runs terrible and only p0300 comes up. Tested all wires and voltage to the new AF sensor and all is good. Tried the ecm relay switch, changed nothing. I don't know where to go from here. Can I test the IPDM? Can I check to see if a cat is plugged? Maybe fuel pump? Please Help.....