2007 Audi S4 Avant 4.2L V8: OBD2 Code 04465/05465 Throttle Drive Angle Sensor 2 Implausible and Limp Mode After Engine Repairs

I'm experiencing a persistent issue with my 2007 Audi S4 Avant equipped with a 4.2L V8 engine. After a recent service visit last month, the car has developed recurring fault codes and now enters limp mode after approximately 15 minutes of driving. The original repair involved addressing multiple oil leaks—oil filter housing, front crank seal, intake manifold, valve covers, engine oil cooler, and valley pan gasket—for over $3,000. The shop replaced these components and reinstalled the front end assembly. Within 30 miles of normal driving, a coolant leak was reported due to an oil-soaked coolant hose, requiring another repair that added $1,500 to the bill. Since then, I've been consistently seeing OBD2 fault code 04465 (Throttle Drive Angle Sensor 2 Implausible), and in some cases also code 05465. The car enters limp mode after about 15 minutes of driving, even after multiple attempts to resolve the issue. Prior to these repairs, the vehicle operated flawlessly with no error codes or performance issues. After replacing the accelerator pedal and performing several throttle body cleanings and adaptations, the problem persists. I'm now considering a full throttle body replacement (estimated at $2,000), but I'm hesitant to continue replacing parts without first diagnosing whether there's an underlying issue such as a loose electrical connection, poor ground, vacuum hose leak or damage from previous repairs. Could anyone offer advice on specific diagnostics I can perform myself? Given the extensive engine work done recently, I suspect that one of these components may have been affected. This vehicle is my only mode of transportation, so any practical troubleshooting steps would be greatly appreciated. Thanks in advance for your insights!