I pulled the codes from my 95 (OBDII) LC. It read P0170 Fuel Trim Malfunction Bank 1. This started shortly after the head gasket was replaced. The mechanic that did the HG replace pulled the codes and recommended to replace O2 Sensor (Front) which I did. It obviously didn't help. Freeze Frame info: Fuel Sys 1: CL Fuel Sys 2: CL-Fault Calc Load (%): 12.55 ECT (degF): 192 STFT B1(%): 8.59 LTFT B1(%): 27.34 Eng RPM: 640 Veh Speed: 0 IAT (degF): 87 Since it looks like it's indicating "Lean", I'm looking for a vacuum leak. But why is Fuel System 1 in closed loop ops (and apparently okay) and Fuel System 2 seems to have a CL fault? What is the difference between Fuel System 1 and Fuel System 2? thanks.