This is actually two different questions.

1. I did a long tube header install with 3"y and cat-back. Now when I pound the throttle I hear and feel a clunk under the car. I have been reading and people say they have similar problems and it's the y-pipe hitting the floor board. HOWEVER, if my car is in park/neutral and I throw the RPM up the 4-grand, I have no "clunk". I would think the motor is still torqing the same wheather it's in drive or park?

Is it possible this noise is actuall a broken tranny mount?

2. I got my computer tuned along with code delete for the headers. Eveything is good except now I have a "bank 2, sensor 1...slow to respond" code. Does this require a new 02, or could this be from the 02 extention.

 

1 what kinda headers my friend did pacesetters and has the same problem the fix to that is poly motor mounts

2 make shure the extension isent loose

 

Headers are SLP. I've geard about doing different motor mounts, but I am cnfused as to how the noise happens only when the car is in drive. Doesn't the motor twist the same wheather or not it's in gear or not?

The 02 is fixed, I just swapped the front and rear, wiggled some wires and we're good. Since the rears are turned off, it didn't matter much.

 

when the car is in gear it has more twisting force on it, not sure why but my old ORP setup did the same thing

neutral was fine, but in gear it was embarassing.

 

no, when in park/neutral, there is no load on it, doesn't move anywhere near as much as it does in gear