ihiryu

iTrader: (7)

I have no idea, but at 2K my car runs super rich, the gauge goes to 12:1, I'll adjust the SAFC to negative, then the gauge will go lean, then bounce back and forth until it goes to 12:1.

Anyone have any idea?

xspsi6

iTrader: (31)

What year sc400? The ecu is most likely trying to fight the change from the afc.

ihiryu

iTrader: (7)

92, nope cause it does it when the SAFC does it when it is zero also

xspsi6

iTrader: (31)

And the air flow meter is set to Karmen? Take the afc out and jumper the brown wire which will set it back to stock and eliminate the afc as potentially part of the problem.

Vrank

iTrader: (4)

ecu going bad?

ihiryu

iTrader: (7)

AFC has been hooked up over five years. Yes it's set to KMV. I'll check the wire on the SAFC though, maybe it's come loose after all this time.

I also think it may be my ECU taking a poop finally though. Since it only does it at this RPM at cruise. It's fine if I got WOT at that RPM range

ihiryu

iTrader: (7)

Well I replaced the ECU with another one, still the same thing. I'm starting to think maybe it's an o2 sensor.

I'm going to try to unplug them to see what the car does.

ihiryu

iTrader: (7)

Unplugged O2 sensors, disconnected FMU all together. Nothing, no differences at all.

ihiryu

iTrader: (7)

Replaced KMV sensor, found a vacuum leak, fixed it. Reset ECU, same thing.