code 171

i own a 97 gp 3.8 engine. recently replaced new egr valve and still getting code 171? what could be causing this code?

P0171 indicates a lean condition. Technically, the short and long term fuel trim values should be checked with a full function odb-ii scan tool to determine the underlying cause(s). Just do a search of P0171 and you will get a bunch of hits.