Recently purchased a 2003 Acura CL-S and had no problems until now. Not really car-savvy and having extreme difficulty pin-pointing what the issue is exactly as it tends to come and go from session to session.

Some info about the car:
- Automatic with transmission replaced at about 172k and currently has 208k on it.
- Oil was done about a week ago along with transmission fluid being changed and transmission treatment added
- Serpentine belt done 5k ago when squeaking started in front tire area
- Car was purchased at 202k and had minimal issues up until now

Some info about the recent problems
- Error codes were checked and show P0122 (TPS sensor)
- One issue that occurs while driving is the car is extremely slow to shift up in that it will hit about 4k RPM and hover until more gas is applied before it shifts. Upon shifting the car "jerks" and makes a hard shift to the next gear up.
- Recently started to have issues with rough idling. That is when in drive and completely stopped (foot on the brake) the car shakes quite noticeably.
- The lights were noted to be dimming and then brightening rather quickly when the car was in park after having some of these issues the other night

Alright so these are the major problems that I'm experiencing right now. I took the car to my mechanic and he said he is unable to replace just the TPS and the sensor itself is not sold in the city regardless. The entire throttle body would have to be replaced and that is on back-order in addition to costing $500-600. Before I go ahead and order a TPS or decide to make the replacement, would like to confirm whether all these issues could be related to a bad TPS or if there may be other problems with the car. The transmission has been good up until now (I know its bad on these cars) and was only replaced about 35k ago so I'm hoping that's not the issue, along with the transmission fluid being changed recently. If anyone has any ideas as to what could be causing these problems or how to resolve them input would be much appreciated!