Here's the deal. I have a 2000 SE and it used to run nice and fast. Recently, it's been running like crap. It has an extremely rough idle and has no power in the power band. It loses all it has at 4000 RPMs. I used to get 35-36 ish mph out of first gear, now I barely get 20mph. I started out with easy stuff. I got a new filter for my CAI, new plug wires, new plugs, changed my fuel filter, and PCV valve. Still ran like shit. I thought the problem might be the fuel pump. I heard about the recall, so I brought it up to a Dealership and they ran diagnostics. They told me I had a dead fuel injector, and that my fuel pressure was fine up until the injectors. So...I got new injectors in it today. I was psyched, figuring I had fixed the problem. I started it up, and it still ran like crap. The only difference is a slight improvement in fuel efficiency. I still have a rough idle, no power over 4000 RPMs, and I'm running out of ideas. CEL is on and shows code PO171 - System too lean. I tested out my EGR and DPFE and they are fine. Anybody have a clue what could be my problem?? I'm running out of ideas.