1998 Dodge Stratus 2.4L Base Model: Fixing P0123 and P1297 with Rough Idle and Stalling Issues

My 1998 Dodge Stratus 2.4L base model has been experiencing worsening idle problems for several weeks. The car now stalls frequently, especially during stop-and-go traffic or when the A/C is turned on. At idle, RPMs fluctuate between 500 and below, causing a rough idle that becomes more severe over time. I recently consulted my Haynes manual, which indicated that a failing Idle Air Control (IAC) motor can cause rough idling under load—such as when the A/C is engaged, during low-speed steering, or when shifting into reverse. These are exactly the conditions where my car stumbles most. To test the IAC, I removed the throttle body and took out the IAC unit. With the engine cold (after sitting for several hours), I powered on the ignition without starting the engine and connected the IAC to its wiring harness. The pintle did not retract as expected—this is typically a sign of a faulty IAC. I manually pulled the pintle fully out, then retested; the pintle still failed to move. After reassembling the throttle body, I noticed that the gasket beneath it was brittle and had broken into three pieces. Due to time constraints, I temporarily reconnected the throttle body without replacing the gasket. The mating surfaces were clean and fit tightly, but there is likely an air leak present. I plan to visit a junkyard soon to purchase a used IAC for $35 instead of the $110 new price, and will also buy a replacement gasket at the parts store. After installation, I’ll update this post with results. A recent incident occurred when I was in heavy stop-and-go traffic—this triggered severe stalling. The car stalled completely while in park and would not restart despite multiple attempts. After letting it sit for several minutes, it eventually started again. Now the check engine light is on. I took it to a parts store where they scanned the system and found two fault codes: P0123 (Throttle Position Sensor - High Input) and P1297 (No Change in MAP from Start to Run). My questions are: - Does this strongly indicate a faulty IAC motor? - Should I test the IAC wiring harness for voltage, or is that unnecessary? - Could improper reassembly—such as twisted wiring between the Throttle Position Sensor (TPS) and IAC—have caused a connection issue? Any advice on how to proceed would be greatly appreciated. I’m especially concerned about whether the air leak from the throttle body gasket could be contributing to these codes or stalling behavior.