I have the (reasonably common) P0120 Throttle position sensor code on my E300D.

I've read quite a few posts about this and the info I have accrued offers me the following possible culprits to troubleshoot:

1. A need to reset the transmission shift points - a recalibration if you will.
2. Throttle position sensor (as per error code) which is part of the pedal assembly?
3. The throttle body position sensor - seems some people have had this sensor go bad and trigger the same code?
4. The MAF sensor - the error code seems to be common between petrol/gas and diesel cars.

In response to these issues I have kvestions:

1. I have done the reset process as follows:
- turn key to on position with all ancillary equipment already turned off to eliminate un-necessary CAN bus traffic - radio, AC, etc.
- fully depress throttle for 5-10 seconds
- turn off key and release pedal after a couple of seconds.
- wait two to three minutes before switching back to ON position
- use DASHcmd app and bluetooth OBD dongle to clear codes.

Within a couple of minutes of driving the code will reappear.

2. I've struggled to find a part number for this sensor for my car - can anyone help and will an o'Reilly's or similar likely have one in stock?

3. Is there a throttle body position sensor with the OM606 non-turbo?

4. Does the 1996 non-turbo car have a MAF sensor? google tells me that not all diesels have or need one, and this being an electronically primitive car makes me wonder...

Any and all responses to the above would be very much welcome!