Running Lean @ WOT please help !!

[dwaynedman]

My car KA24DE 96 S-14 OBD2 Runs and idles great, approx 14.8-15.2 AFR @ idleCruising speed under soft pedal pressure 14.7-14.2 AFR@ WOT on hills or straight, it dips to 12.5-13.0 AFR for a couple seconds then goes off the chart lean past 17 and cuts a little "hesitates" It takes some time to come back down after letting off throttle and applying cruising pressure again. Tested MAF and TPS both good, tried bumping FP up to 40-42 lbs with no change. Replaced lazy front 02 sensor with no help either. Suspecting faulty injector, but all test out at 11.5 ohms. Cannot put my finger on where it is coming from. I was running a full KA-T setup, and have put it back to stock after melting through a valve. With stock ECU and all, and still am running lean.

Currently on car is :

Walbro 255Adjustable FPR264 Crower Cams3" full exhaust

Any help is appreciated.

Thanks,D

[dwaynedman]

So I seem to have partially fixed my problem. I tested the ground to MAF and found I had 48 ohms resistance. Wired ground straight to engine block, and most of my lean condition went away. It now dips at WOT to 13.5 then 12.5 then 11.2 under hard load, but around 5k RPM it still shoots over to full lean until I let off the gas and stomp it again. After a couple seconds of load, it shoots to lean again, and I can take my foot off the gas and get on it again goes back to 12.5. So basically it is still lean under hard load, just not as bad as before. WTF is going on ???

ThanksD