i've got a 96 4x4 with the 351 and i have some codes coming up. it' doesnt have any CATs but the O2 sensors are there and plugged in. i get the EGR code but not really sure about the other ones. Any help would be appriciated

po443 evap emission control purge valve c fault

p0401 egr flow insufficient flow

and a p1409 manfacurer control auxiallary emmision control

 

So I'm assuming you have test pipes in the place of your cats with possibly a defouler hooked up or the O2 sensors are up and out of the air flow to trick the computer. Is this an issue that just popped up or is this a new issue that popped up after installing test pipes?