Originally Posted by Jhill

Please do not ever say a code reader will pinpoint exactly what is wrong. All a scan tool will do is give you the issue the pcm is seeing and what area the problem is in. This is where knowledge and diagnotstic techniques kick in to do testing and troubleshoot the sensor, wiring, signal etc. This is what separates a true tech from the parts changers. From his story it sounds like he has already been hit by the parts changers and this second shop sounds like they are ready to start throwing more parts.

Op it's time to find yourself a reputable shop that will actually do diagnostics, and don't expect it to be free or you can bet you've just found yourself another parts cannon shop.