cdk4219

I rercently put an 98 LS1 T56 into an 88 RX7 and got it up and running. The engine runs good in open loop but as soon as it gets to closed loop it pulls 0131 and1051 codes sensor1 bank 1 and 2 low. I have checked the wiring ato the sensors and it looks good and I have been picking John B's knowledge on thisand tried a couple of things he has suggested. One of the modifacations that I had to make was lengthening the MAF wires to relocate the MAF about 14" from the stock location. (You can see the intake on www.thewrongmotor.com,not my site) the pictures are under contributions name Chris K.
The way I am leaning is that the MAF might be bad, The pcm might be bad, my wire lengthening job(which are soldered but with copper wire) might be changing the resistance. I have also checked for vacuum leaks but cant find any. I know the engine is lean by the way it actsbut I dont know how to richen it up.
P.S. Mods from stock K&N airb filter with 3.5" intake tract, Dual 2.5" catless exhaust with MET rear O2 simulators. <img src="graemlins/gr_devil.gif" border="0" alt="[devil]" />