I have a 98 accord with a 4 cylinder auto. I got codes PO170 & PO171. I cleared them and installed a new O2 sensor at the engine exhaust manifold. It went fine for a few days and then the code came back. Any ideas on what might be wrong or what to try next.

Thanks,

 

Some things to check: fuel pressure, valve adjustment(too tight), vacuum leaks, egr hanging open,

 

I have the sema problem with my accord 2000 LX 4 clndrs.Please somebody help!