The tps is a little high,i would try setting it to .42 key on/engine off, i would wait and do this after resetting the IAC though.
Also as mentioned for the IAC, i would remove it to inspect and clean and reset after reinstalling it. I usually just spray the tip and shaft/spring with throttle body cleaner then dry it with a paper towel and also spray/clean out the throttle body while i'm doing this.
You can find the procedure for resetting the IAC on the site below.
www.vortexbuicks-etc.com
IAC (Idle Air Control) Adjustment
The IAC function maintains idle quality through commands from the ECM, but, has
NO impact beyond the idle range. Further, the IAC reading means nothing once the car is off idle.
Idle speed is set by the chip, not by the
IAC adjustment screw. Looking at the
inside of the throttle body, there are two holes in the lower portion fore and aft of the throttle blade. At idle, the blade is essentially closed and air enters the front hole, goes past the IAC plunger, and exits behind the throttle blade into the plenum. The IAC plunger is pulsed by the ECM to maintain a steady idle with varying engine load.
When the IAC is adjusted, we seem to typically look for IAC counts on our scan tool somewhere between 15-25
when the car is in Park, the engine fully warmed up, and the A/C is off.
The lower the IAC number, the less control the ECM has over the idle as the throttle blade begins to be opened. This setting may not be as critical as we often make it. You may find your car idles just as well at 40 counts as it does at 15.
With car in Park, engine
fully warm, A/C off, look at the IAC counts on the scan tool. If you wish to lower the count number, turn the
adjustment screw clockwise. To increase the counts, turn it counterclockwise. Turn the screw a small increment, turn the engine off, and restart. This insures that the IAC resets and confirms the adjusted number. Continue until the desired number is achieved. Often, on stock set ups, about 1-1 1/2 threads of the adjustment screw will emerge thru on the lever side of the throttle body. Restarting also rezeros the tps as stated in the prior section and removes any effect on idle speed that may have occurred due to tps movement. The IAC counts will probably be 30 counts, or more, higher on a cold engine than on a warmed up engine. The counts will also be much higher in gear as compared to Park, and, higher with the AC turned on.
Remember that the IAC adjustment will change the TPS and that if the TPS moves past 0.46 volts, the idle may increase in speed as the ecm no longer thinks the car is in idle range. Therefore, if you are going to decrease IAC counts very much, it is a good idea to first lower the TPS down to 0.38 volts or so in order to prevent it from rising out of the idle range as you adjust the IAC.
It is not a bad idea to clean the throttle body out periodically with carb cleaner to keep the passages clean and to insure that the IAC function works correctly. Remove the IAC from the housing and clean any carbon or gum off the tip of the plunger and clean the seat as well. Don't power up the IAC when the unit is not installed. Otherwise, you may find the plunger is pushed out of the sensor. When reinstalling, very little torque is required. Just tighten enough to compress the gasket to prevent an air leak. Over tightening may crack the plastic interior of the IAC.
