major problem, but no code

[#z'sx#]

My 2001 Xterra has been problem free until now. It recently started chugging/bucking. I've done replaced:serpentine belt, fuel filter, knock sensor, spark plugs, plug wire set, distributor rotor and cap. Fuel pump is fine. It still feels like it's misfiring, and now stalls out-- which it wasn't doing before.

The knock sensor code was showing, but that's taken care of now. No codes are showing up now and my mechanic and I can't figure out what's going on. Any suggestions?

Thanks!

[Rev_D21]

Did you check the connector for the fuel pump at the top of the sending unit for corrosion?