I am wanting to weld in a oxygen sensor bung and have seen there is a certain distance (approx 12") from the elbow it should be put. Problem is, I can't take off my downpipe, it's welded solid to the test pipe. I can put it in one spot that I can weld all the way around, approx. 4-6" down the pipe from the exhaust elbow. Will this give me correct reading when I am tuning the AF ratio with a hand held LM-1 tuner?