replacing the intake manifold gaskets on 2000 Chevrolet Suburban 1500

I am getting 2 Lean codes P0171 and P0174. My mechanic says that my intake manifold gaskets are leaking. After replacing them he says that I have to replace the drain and replace the oil. I thought that it was antifreeze that ran through the Manifold not oil. Oil in the valve covers. Thank you

by in Poughkeepsie, NY on March 02, 2010
2 answers
ANSWER by , March 02, 2010
He probably just advising you that the oil needs changing as debris from the old intake manifold gasket has possibly gotten into the oil
ANSWER by , June 23, 2010
My 2000 GMC was throwing the same codes I found it was the fuel pump. My truck would run great most of the time I couldn't believe it was the problem. shop wanted 500 bucks i bought one on e-Bay & installed it myself problem gone cost 64 bucks