I have a 2000 GS-R. I changed the O2 senor out back in june. I still have the check engine light coming on and i have a couple of troblue codes. Here they are. P0170 Fuel Trim Malfunction and P0172 System too rich. I called the dealership and they have yet to get back to be on this. There is a problem with the vtech cause it wants to kick in at 4500 rpm's. Can help me please.