Well... keep throwing P1131 and P1151 codes. Noticed it only does it when the car sits in temps below 30 degrees. Never throws it while its driving... always during a warm up in the morning after a cold night. Went through my intake after MAF found no leaks. No audible or visial vac. leaks. There is a slight exhaust leak after the header prior to the cat on the pass side but it never threw a code until it got cold. I'm not experiencing any rough idle or anything so just a little confused as what else it can be. Did a search but just wnodering if anybody else started getting this once it got cold. Thanks for the help!

 

an exhaust leak before the front o2 sensors can sometimes cause a bad reading at the o2 sensors tripping a code and sometimes causing really poor performance. thats what i would say is it.