Error Codes & More HELP!!

[SUSS8]

Puchased a new VR Calais and had it for about 2 weeks. Just did a Error Code Check on it and came up with these.

Error 12 - No RPM Signal
16 - ECT Sensor Voltage Unsteady
21 - TPS Voltage High - Auto Trans Code

Any Help with what they mean and how they can be fixed? Also, Another thing I noticed is that I may be at the lights and when the car is sitting for a little bit it starts to idle funny like its about to stall then pick up on the revs but eventually does stall. Atleast twice a day. I found that the Timing is advanced but anyone else had a similar problem to me and how did you fix it?

Thanks In Advance Guyz!

[Brett_jjj]

Code 12 usually means everthing is ok with the engine management systems.It just shows error code 12-no RPM signal because the engine is stopped.It also shows code 12 before and after any set error codes are displayed.As for the error codes themselves,check the wiring to the sensor,make sure its clean and tight.Clear the error codes by disconnecting the battery for a couple of minutes,then drive it again for around 20 minutes or so,then recheck for any set errors,if any of the error codes return,replace the sensor thats showing up as faulty.Sensors wear out over time just like any other part.

[moff_man]

thinking out side the box, but check your charging rate, you have 2 voltage related codes, this may be a issue. also if the charge rate is good than check the tps, this could cause an unstedy idle.

[SUSS8]

Ok I just changed the Coolant Temp Sensor, TPSensor, New Leads, New Rotor Button, Dizzy Cap. I disconnected the battery to reset the ECU. I ran the car for a bit and on idle was perfect. While I was driving it home it started playing up again. The idle went all funny like it was going to stall then the Engine Light came back on and the auto would not change into any gear was just stuck into 1st. I pulled over and turned the car off for about a min or so turned it back on and drove it home. Since doing all this my Fuel Economy has gone south as well as there being no change in how it was running before.

[SUSS8]

Also forgot to add that before I was getting code 21 not i am getting code 22!