Boy oh boy, its been 2 years since ive been on here...wow, so how is everyone doing??? I decided to put the problem that we have been having up on here since you guys have been so helpful in the past. We have been having trouble over the past few months with this thing. In Case you guys dont remember the taurus we have is a 2001 Vulcan with the if i remember correctly AX4S trans??? Anyways a couple months ago we started having trouble with the car running really rough all the time and it would feel like it was missing especially under light throttle and the engine being under a load whether going up a slight hill or something like that. Also we were getting a engine code of P0133 which i think was an 02 Sensor code and it said CKT slow Responce Bank 1 Sensor 1. I ended up clearing the code and it hasnt been back since. Not long after clearing the code we did a tune up on the car which involved replacing the air filter, fuel filter, spark plugs, and the plug wires as well. The car after doing this is much better, but still isnt quite right. This is my grandfathers car and he doesnt drive it much just now due to a knee replacement and having surgery. Upon replacing the plugs, some of the old plugs were gapped at like .070" which is way above the .044-.046" that it requires( this was set at the ford dealer back at its 60k service). I am assuming this was a big problem to why it was missing since it runs much better. Now as of recently when you start it up and say put it in gear but keep the car stopped by holding the brake pedal it will feel like its missing bad but once it warms up it seems just fine. My question here is what could be causing this. Does the engine code I got mean anything? Should I replace it? Also Can anyone tell me which O2 sensor this is and where it is located? Its not a real hurry to figure this out but I just wanted to put it out there to see if anyone could come up with anything or had this issue. Thanks....Brad, P.S. Glad to be back on here once again!!!!