hey guys im a little confused.. i used to be getting the p0420 code and i reset the code twice and since then (about 2 weeks) it hasn't gone on again. today after i drove my it i decided hey lets put my obd II scanner on and see if anything comes up. I end up getting the p0171 code. Are these two related in any way? ik the p0171 may have something to do with the up stream o2 sensor could that be the problem? and why hasn't the p0420 code gone on?
Thanks
Chris