Failed Emission Test..., ...running too lean Options

[LatinKraze]

I was told by the Smog shop that I was running too lean. They said that I wasnt getting enough air and the Air to Fuel was off by a bit. They said that maybe if I removed the air filter while doing the test it might help for it to breathe better. So I removed it and they ran the test again and the numbers came back 5x worse. I have to get 1.2 reading at the most, with out the filter it ran at 10.0-15.0, and I am currently at 2.08 with the air filter in. They said it might be the Mass Air Flow Sensor. I went to the dealer and they said that my car does not have one. I think it might be my O2 sensor. Can this make my car run lean? I dont want to change them out cuz the previous owner cross threaded the mofos. Where can I start fellas? Any suggestions? Thanks

-Ivan-

[LatinKraze]

Im going to take her to my mechanic. He said he'll run a diagnostic on tuesday. Thanks for the input guys. Weird thing is that I was on the highway a few months back and when I downshifted to 4th to pass a big rig my CEL came on. It read that the secondary O2 sensor was faulty. I reset my codes, replaced the sensor, and it came back after a while. Only seemed to turn on when I hit high RPMs. Now that I reset it again for emissions, I raced the hell out of it to see if the CEL light would come on and it hasnt so far. I've "raced" a 04 Mustang GT, 90 sumtin Firebird or Trans AM, and a GT-S and still no CEL light. Do you think it might have been a clogged injector? I heard that pushin her hard sometimes makes the injectors flow better afterwards.