Drag Strip tips and advice needed.

Well, The night did not go as planned. I got 3 runs in very quickly. 30 minutes. Horrible results. 14.0 best, 14.7 worst. The car did not have any umph at all. my son running next to me said my exhaust was blowing out lots of smoke. After I got home I looked at the clamp on O2 sensor. Tons of black soot all around it and the connection just 8 inches after it. It makes me think that the EFI was trying to get the A/F ratio correct and the sensor was not getting the correct info to adjust the fuel properly. So I have to weld the sensor on and get rid of the clamps. I will also pull some plugs and check them to see if my suspicion of overly rich is correct. After the thid run as I was pulling into the pits to take it home there was some popping from the exhaust. Then after I got home as I was pulling it into the shop, there was more and bigger popping from the exhaust. Unfortunately, the data-logging did not work.
Also the exhaust tips are sooty. I will pull the plugs tomorrow.