Contour Enthusiasts Group Archives Forums General Troubleshooting Engine code 171 & 174

My CEL has been on for months and I finally had the codes read last weekend at Autozone and these codes came up. "Lean 1 & 2 banks". The car runs great, smooth idle, runs cool (never above the N in Normal). New spark plugs, wires, fuel filter. The gas cap has good vacuum and there are no vacuum leaks in intake that I can tell. Could this be the O2 sensors or is there something else I should check? One thing I haven't replaced yet is the PCV valve since I bought the car 10K miles ago.

Sounds like upper O2 sensors on the front and rear bank. Especially if you have more than 50K miles, they are probably due for replacement. I guess the secondaries could be stuck open, but I don't think it will cause the CEL you are seeing. Can you feel them open up around 3800 RPM?

The car's got 127,000 miles on it and I really don't know when the O2 sensors were replaced last. I guess it wouldn't hurt to replace them. How many are there on a 96 SE?

oh yeah, about the secondaries... I would say that they are operating effectively with no hang up or stumble.