1993 Buick Lesabre Car Accelerates on its own

My 1993 Buick Lesabre has a tendency to accelerate on its own. I have already taken numerous steps to attempt to fix it but nothing has worked. I cleaned the Throttle Body and the MAF sensor. I replaced the IAC valve and the Intake Air Temperature sensor with brand new ones. I replaced a few of the rubber elbows that join the vacuum lines together (as several of them were badly cracked), so as far as I can tell, there arw no vacuum leaks left. I also checked for trouble codes using the paperclip method, and all it gave me was code 23, which in my car is the Intake Air Temperature sensor - low reading. After I replaced the sensor, I checked again and all I get is code 12, so no more bad codes. Is there anything else I could've missed? Thanks.