Help guys, I am having the weirdest problem. When I first start the car, the a/f gauge shows normal readings, with 0.9 at WOT. But after driving a while, the a/f gauge stops fluctuating as much, and at WOT, typically shows 0.6 to 0.7. Sometimes it will hit 0.8, but never 0.9 when I floor it. That means I am running lean right? Also, when cruising, it only fluctuates up to 0.6 and no higher. And is it normal for the a/f gauge to show nothing after I let off the gas, until I almost come to a complete stop?

Why does the low a/f ratio only happen sometimes, and if I stop the car, and restart it, then it is back to normal again? Help!

o2 sensor is going bad? or wiring to the o2 sensor is bad? It didn't used to happen, did it? Like when you first installed the a/f guage it was normal (bouncing from low V to high V unless at WOT).

I just replaced the o2 sensor about 3 weeks ago. I think it started after I changed the plugs and kept regapping them. Right now I am running 0.036" gap on NGK 6 heat range plugs with a ported and milled head. The strange thing is that it is normal at first, then gets worse. But if I turn off the car and turn it back on, back to normal again.

I'd double check the wiring. Might be a loose connection but other than that I'm not really sure.

I don't have the voltage A/F gauge, all I have is the blinky light thing. But the same thing happens too whenever I let go of the gas, the gauge gives a lean reading, goes to the redzone, and sometimes, not even register any reading. I guess this is normal though. Might be some logical explanation for it. If it isn't normal though, hope someone can give insight into this.

could be a bad ground connection.

I don't think its the wiring or anything, because if I turn off the car, and restart it, it goes back to normal for a while to I do more driving. Then, even at idle, it will hit a max of 0.6.

Are you still having rough idle?

"The fastest draw is when the sword never leaves the scabbard,
The strongest way to block, is never to provoke a blow,
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Michael J. Kulaga
e-mail: Michael_97RS@2gntDSM.zzn.com aol IM: MJKulga
http://highlander.dsmpower.com/

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Yup :(

Do you have a CEL for lean? I would think this could be a bad MAP sensor screwing up your fuel curve

"The fastest draw is when the sword never leaves the scabbard,
The strongest way to block, is never to provoke a blow,
And the cleanest cut is the one withheld."

Michael J. Kulaga
e-mail: Michael_97RS@2gntDSM.zzn.com aol IM: MJKulga
http://highlander.dsmpower.com/

All Motor Beast in the Making

Injen CAI, 55mm TB, Hooker 4-1 Stepped Header, GS-T Muffler, AFX UDP, S-AFC, 8.5mm Magnecor Wires, SS Clutch Line, NRG Susp. Motor Mount Ins., FU/RU/RL STBs, TSW Blade 17x7.5, Bridgestone Potenza RE730 215/45ZR-17. Front KVR Cross-Drilled Rotors and Carbon Fiber Pads

To Be Installed: Ported/Polished Intake Manifold, Rear disc brake conversion kit, SS Brake Lines, Rear KVR Cross Drilled Rotors and KVR Carbon Fiber Kevlar Pads

I'm not for certain, but if the connection is secure; if you've tapped in the correct wire for the O2 sensor; if the car idles fine; if there's no "lean" CEL, then that only leaves you with a bad air/fuel gauge or o2 sensor. I still think it might be a bad ground point, or a loose connection where you tap into for the O2 sensor. Just my guess though.

Hmm now it's acting normal again, except at WOT in first gear, between 3500 to 4000 rpm's, it drops from 0.9 to 0.6 and then back up to 0.9. It's weird. Why would it always do that at a certain rpm range?

check all the connections again. maybe the vibrations created by the engine is messin up your readings.

and i second the thought of checkin your ground or changing it to a better spot.