I keep getting this code intermittently when I've pushed the car a little hard going up and down hilly terrain. It only happens on the Interstate (60mph+). Any enlightenment out there about what might cause it?

Quote:

Oxygen sensor not switching - system is or was lean Left or Front HO2S


Midnight Red '95 Contour SE. YoDude quasi-dual cat-back w/ Dynomax muffler. SVT UIM and TB. KKM True-Rev CAI. Pre-98 SVT front and SVT rear conversion, YEAH BABY! Alpha Kappa Psi