Throttle Body OBD2 - Differences?

[Matt W 4]

Been having problems with my TB, it won't calibrate properly. You can hear it buzz (it receives power) but no clicking (stepper motor not doing anything). So I bought another one from eBay looked OK nice and cleaned up OK. However when I put this on the car it idles really high (1500rpm) and I get two new fault codes

00524 - Knock Sensor #1

00268 - Solenoid Valve 6 (N93)

Now what doesn't make sense to me is why does the 2nd fault that comes up is from an automatic gearbox which I don't have. So are there differences between OBD2 throttle bodies. As this new throttle body has the same part number just minus the 'A' and was produced in 95 where as my car is a late 96.

And which TB is correct as both of them will not calibrate. Or does it mean the 2nd TB (from eBay) is working but won't calibrate as there is a problem with the #1 knock sensor or wiring to the ECU

Thanks in advance

oh and the reason I swapped the TB is because the car stinks of petrol (no leaks found any where) and it doesn't idle properly. If the voltage on G127 reaches 3.94v then it fluctuates. Anything under 3.94v and it idles fine...