Originally Posted by MLaborde
Can a bad O2 sensor cause lurching & bucking in 1st & 2nd gear?
Yes, as well as back firing. However there are several faulty components that can result in the same effect. There are several threads on fuel related problems. Faulty O2 sensors, faulty Throttle Position sensors, faulty fuel pump module are just a few components that could be the cause of what you are experiencing. My TJ does the same within the first five minutes after engine start (both cold and warm engine), after a few minutes of just idling the problem goes away, until the next engine start. Cheers.