I only have the drivers side O2 hooked up in my 93 bird. The other one was broken in the engine swapping. I do plan on replacing asap. It doesnt seem to affect the driveability at all, good idle, good power, smooth runner. The CEL comes on after its warmed up and goes on and off, of course for the O2... My question is does the EEC read the O2's in closed loop, like when its cold? Thanks.