Most likely a vacuum leak. Check vacuum lines, throttle body and EGR valve. Also the #1 reason is the intake manifold gasket leak. It needs to be replaced.
None directly - that I know off, however, you might try Saab and I know that the V6 is the same thing and that they are the same car pretty much.
Drive to your local parts store or GM dealer and they can tell you what it is.
Check the fuse/relay panel box adjacent to the battery, under the hood.
The knock sensor is located on the backside of the engine to the left of the oil filter, it is round with a 1 wire plug on it and a round base. I do not know the torque spec, but when I replaced mine I made it tight enough not to back out on its own.
You reset the computer with an OBD2 scan tool. Or some times if it is not a hard code by that i mean a real problem you can disconect the batt. for a hour this some times work but the newer cars are harder and harder to do this with
the_front_end_of_the_vechicle_will_ethier_allow_the_front_to_droop_and_it_will_also_end_up_being_stiffer in_the_ride.Another_way_is_too_bounce_the_car_by_hand_watching_for_the_number_of_bounces_that_it_takes more_than_two_is_considered_sloppy_and_in_need_of_replacement.
Most A/C systems have a sensor that will automatically stop the compressor when the R134 refrigerant runs low or leaks out. you will be able to tell if the pump is working by having someone turn your A/C on and off in the car with it running. If the clutch on the pump is not engaging and disengag...
You have to take the door off to remove any panels. You will have to drill out all the plastic rivets around the edge of the door. Of course you will have to replace them all with new ones. If I were you I would get a shop manual to help you with this. It's very time consuming.