1999 Toyota Corolla 1.8 ce O2 sensor

Question

i have changed the o2 sensor, plugs, wires and vcg. car still hesitates when i take off, feels sluggish. cel came back on.

Answer 1

P0171 Fuel trim lean

Lean condition are more air to fuel ratio, on this engine it is important that the timing be check,Most lean condition are caused by vacuum leaks one place to check would be the intake manifold gasket,