how do you change +or clean the egr?
on 1997 Nissan Maxima

failed emissions - cdes p0400+p0300+p0443

Asked by for the 1997 Nissan Maxima
2 answers
there is lot more to the egr code, 400 than just replacing the valve. you need to have it checked to verify. there is a lot more than the valve in the egr system
300 is a random missfire
443 is an evap code.

i agree with mastertech. the egr could be causing code po300 but not the evap,seek a proper diag and est as to not waste time and $