So I cleaned the throttle body, and while I was at it figured I'd clean the MAF too. So good news - the check engine light is gone, but now the throttle response is weird. Started fine, but as soon as I touched the pedal engine revved up but did not return to idle (stayed at about 2000 rpms). Stepped on the pedal again and rpms went up further but did not come back down. Put it in gear and rpms dropped (still higher than normal idle though) I have no idea what's going on, any ideas? 
I had this problem with my truck and all I did was clean the intake with a throttle body cleaner make sure you get in there pretty good and get all the gunk out of there, I do remember my truck idling high after I did this but it went away after a few days of driving.
If that doesn't fix the problem then you probably have a bad TPS sensor, the harness is rubbing and causing it to malfuntion, bad connection at the TPS, water or corrosion in connector or sensor, and not to common bad PCM.
A way to check it is if you have a digital meter or a scan tool, you can monitor the TPS sensor voltage when they are at idle or WOT(Wide open throttle) and they should be at idle= .5volts;full throttle-4.5 volts
You can also check for 5 volt reference at the connector. If it checks ok, check the ground circuit for opens or shorts. If the signal circuit is 12v it has shorted out, trace circuit for short to voltage and repair, it could be a connector rubbing on something that has shorted out. Look for water or corrosion in the connector and clean it and apply dielectric grease to prevent corrosion.
If everything checks ok , then you definitely have a bad TPS sensor which requires the entire Throttle body to be changed. I would buy it and install it myself it's not that difficult to swap out.
or you could just take it in to the shop and pay to get it fixed, but just to clean the throttle body is $140-160, I can't imagine what they charge for troubleshooting and fixing the problem would come out to be probably $400-$600