Quote Originally Posted by old guy View Post
I am struggling with the connection between the MAF and throttle body symptoms. The fact that your engine won't start with the MAF plugged in but will run if you plug it in after starting. Typically that would be an indication of a rather severe air leak somewhere. Which could still be the case. Once you have the opportunity see if you can get 10→15 minutes of drive time and recheck the fuel trims.

I mentioned that I expected the STFT to be bouncing around ± 0%. If it wasn't bouncing but just staying as a fuel add that would be an indication that the idle fuel trim wasn't through adapting yet and would eventually settle well above 10%.

Now go eat dinner!
Edit: Just a few more points. The instantaneous or Short Term Fuel Trim is the immediate adjustments being made by the ECU based upon feedback from the front O2 sensor. If at idle the ECU has to continue to add fuel above the base map it will start to adjust the base map up until it no longer has to continue the add. In your case the base map is adding 9% at idle. If your STFT (currently at 5%) stays above 0% the base map will continue to increase until the STFT hovers around 0%.

As I mentioned the fuel trims reset to 0% every time you clear the ECU. Once you start driving the STFT will do the same thing for the long term partial trim. Your base map is currently set at 0%. As you start driving the STFT is going to either add or subtract fuel based upon the front O2 sensor reading. If it continues to add fuel the ECU will adjust the partial trim base up until the STFT no longer has to add fuel. This takes a few minutes of driving for everything to adjust out.

This will give us an indication as to how your fueling is operating and may give us some insight as to why the TB won't reset.