Just trying to find out if anyone has experienced getting PO131, PO137, PO151, PO157 codes??? I get all four which refer to all four O2 sensors running lean. Should I go ahead and replace the front two O2s (pre-cat) and just delete the codes for the back two? My performance does seem to suffer at times as car will run rough and slower than normal. I just don't want to replace any parts that aren't going to help the situation.
WS6Firebird00 has been very helpful in giving me some ideas and I am definitely open to any other input. THANKS
98 Z28 A4 275/40/17 Nitto DRs, MTI air lid, exhaust cutout, free airbox cutout, Fuddle 3400 2.1, B&M Supercooler, 3.42 gears, NGK TR6 plugs, MSD wires, HSW wet kit