P0171 2004 Honda Accord -

Question

04 accord 2.4 Vtec, p0171. No visual leaks found. PCV valve Ok. MAF cleaned. New tune up w/ spark plugs &air filter. cooling system Ok. Engine still a bit rough. P0171 keeps coming back on and on. Please help.

Answer 1

Hi there,

I would check for vacuum leaks around the intake manifold. This can cause a rough idle. Also, if there aren't any vacuum leaks then the next step would be the front O2 sensor. If it's running out of range it can cause the engine to run lean.