Question

My 1997 Honda prelude is throwing P0171 and P0170. I have a cold air intake with a clean filter. where do i look next?

Answer 1

P0170 and P0171 Lean fuel system

 Lean system can because by vacuum leaks susch as the EGR being slighly open at idle . this will also cause a rough idle or any vacuum hose that is disconnected. such as the PCV valve. (PCV valve has tendeny to shut close) . This engine that is equipt is a speed density type which uses a MAP (manifold absolute pressure)  .Mechanical condition tends to create the lean condition such as low fuel pressure the specification are 47 to 54 psi with the pressure regulator vacuum hose disconnected.