Monte Carlo Forum - Monte Carlo Enthusiast Forums

Hi all,
Although I have had my 2005 Monte Carlo LT 3.8 for a little over 3 years, I am now having the standard GM issues (ABS sensor, O2 Sensor, etc). I did the upper and lower intake gaskets myself. Not a particularly HARD job, just time consuming, and annoying. My new questions are:
1. I see a lot of posts about cleaning the MAP and MAF sensors. Where are they located? How do I clean them?
2. Also my transmission is shifting funny. It winds out 1st, slams into 2nd..then slams into 3rd about 2 seconds after it goes into 2nd. Coupled with this is a strange whirring noise at higher RPM's. I have recently been getting a P0140 code which I know is the O2 sensor. Could this be causing the tranny to hard shift? I am HOPING (and somewhat praying) that SOMEONE here has fixed the shifting issue by changing the O2 sensor. The reason I do not think it is the tranny and its electrical is because when I reset the codes (whether they are present or not), the car shifts normally for a few minutes, the noise goes away (and it sounds brand new)...but then BAM...back to the way it was- hard shifting. Sometimes (in the morning, during my commute 20 miles to work), it is absolutely fine. My trip home in the evenings, it tends to start about half-way home or so. Can anyone offer some advice or experience with this? I am well aware of the solenoid NIGHTMARE that is to take the side cover off the tranny...12 hour job for 30 seconds worth of changing the solenoids..I am DREADING THIS JOB. PLEASE tell me it's not that. Any help would be greatly appreciated. Thanks in advance.
-P