86 Ranger code problems

the vehicle is an 86 ranger with a 2.9 5speed
Ok i have 4 codes on my snap-on mt 2500
1st is (12) can't control rpm during hi-rpm check
2nd is (42) ego not switching, rich exh (bank-1)
3rd is (33) insufficient egr flow
4the is (25) no knock signal during self test

a little background. vehicle was running fine and just stopped. i checked the fuel pressure an wala no fuel pressure. I replaced the low pressure fuel pump in the tank and put in a new fuel filter. fuel pressure is great now. I started it up and it runs, but runs poor. so i checked it out and it has all these codes. i checked for vacume leaks. none! now remember it was just fine before the fuel pump went out. I cleared the codes and then checked again. It comes up with the same codes every time. Any Ideas why all this would happen, or what it is would be appriciated. Thanks in advance Matt