I currently dont have HPT, just a scan guage (aeroforce)
My 97 l67 seems to be running rich with a -10 to -16 LTFT command at light to steady cruse. I dont know what temp it enters closed loop, my guess is 140* since the LTFT bellow 140 are 7-10, but as soon as it hits 140 it goes pig rich and can feel its down on power. Just wondering what might be causing this. The only DTC I have is for my bank 2 heater circuit since I removed my cat and rear o2. Only mods are a thrasher CAI and a stock 2.5" dp to a 3" mid pipe with a 3" glasspack to the stock 2.25 y pipe.
Possibly related; my #2 cyl has an oil control issue. The plug in that cyl shows heavy unburned oil deposits. On heavy decel (engine brake) and neutral rev bounce (rev limiter) the exhaust has an oil smell. Seperate topic; but that cyl has 150psi and is within 10% of the others (150-165), that show zero signs of deposit. Exhaust shows no sign/smell of oil on morning starts so I dont think its valve seals. Maybe stuck/wore control ring but good compression rings?