Throttle Position Sensor High idle and High RPM's

Problem started a while back where car would go into basically cruise control when took foot off pedal. I then realized it was idling very high (There is no idle gauge, but sounded that way). After a couple days it started stalling especially in idle.

I went ahead and finally purchased a OBD scanner tool and read codes. I was getting a P0121 (Throttle/peddle position sensor/switch A circuit range/performance) and a P0001 (fuel volume regulatory control circuit/open) together with a old P0420 (catalyst system efficiency below threshold).
At this point of time car would only drive a mile or two before stalling and I would have to wait about seven minutes for it to relax before starting it up again.
I decided to replace TPS and did that with a cheap autozone $35.00 a piece. (What a pain getting those screws out. Ended up cracking the old TPS and then cracking new one and putting in with only 1 screw.)
Car seemed to work fine for about a week. I went ahead and reset codes and of course right then car dies again.
Here's info I'm getting. Car idled at about 1800 rpm's and it goes up from there. Throttle position at startup is at about %38 (!). When driving car throttle acts erratically. Does not work contingent on pedal. Goes up and down erratically.
This morning started up car without the air conditioner and miracle the throttle was open about 0.5 RPM was at about 700 and throttle opened with direct correlation to gas pedal! After arriving at work (only a few blocks away) tried a few times and all was well. I then turned on the air conditioner and all went crazy again exactly as before. Turned off the air conditioner and stayed same (with Throttle position and RPM). Turned off car and restarted and stayed the same erratic.