OK. Here is what I would do. First, check for any signs of a vaccum leak on the front bank of the engine. Spray some carb cleaner around the intake and see if the idle smooths out a bit or increases in speed.
If that doesn't show any leaks then, I would replace the front O2 sensor(the one in front of the converter) on that bank and clear the codes. This will reset the fuel trim so the computer isn't using the stored bad fuel trim to run. It should reset the fuel trim back to 0 which will make it learn new fuel trim.
Hope this helps! Thanks

OK. The O2 sensor I am speaking of it the first one on the front of the engine. It may be right in the exhaust manifold. It will be before the converter on that pipe.
Try disconnecting the battery for the code reset. I am saying this because the vaccum leak should be what caused the fuel trim code. You might want to check the plugs in the front of the engine and make sure they are still in good shape.Clean I mean, no carbon buildup yet or fowling. You can most certainly wait to accept. Like to have you fixed first! Make sure the firing order is correct as well. I think you are dealing with a couple of different problems here,so we have to take it one at a time. Make sure the cap and rotor are in good shape to.
Here is the firing order

OK. I think you need to check fuel pressure. It sounds like the fuel pressure might be to low for the wide open throttle jump on the pedal to keep up with the demand. It also appears it may be temp related which could be the ect sensor. Here is some info on the temp sensor. I am not sure if mazda uses this for both the guage and the engine computer or just the computer. It sounds like you still have a lean fuel mixture happening. Hope this helps!
OPERATION

The coolant temperature sensor is a variable resistor that is influenced by temperature. Which means, as the temperature changes, so does the resistance inside the sensor. The computer reads this change in resistance to determine the operating temperature of the engine. It uses this reading to determine proper air/fuel mixture and ignition timing settings.

See Figures 1 and 2

This test can also be performed with the sensor still installed in the motor, provided the engine is at the same temperatures as given for the specifications.

Fig. 1: To test the sensor while still installed in the engine, verify the temperature of the sensor then take the resistance reading

Fig. 2: The end of the temperature sensor can be submerged in cold or hot water to check the resistance

1. Remove the thermosensor.
2. Place the sensor in water with a thermometer and heat the water gradually.
3. Measure the resistance of the sensor and compare to the following values:
   • -4°F (-20°C)-14.6-17.8 kohms
   • 68°F (20°C)-2.2-2.7 kohms
   • 104°F (40°C)-1.0-1.3 kohms
   • 140°F (60°C)-0.50-0.65 kohms
   • 176°F (80°C)-0.29-0.2 kohms

OK. Did you clear the check engine light after replacing the ECT sensor. Sometimes you have to reset the fuel trim to start back at zero,otherwise it may be using old fuel trim which was calculated wrong.
Were you able to check the fuel pressure? I would say if the fuel pressure tests good,put a new mass air flow sensor into it. Bad hesitation is normally fuel pressure or mass air flow sensor. I think we hafve narrowed it down pretty good. I like to try and eliminate everything else before going with the mass air flow, it is a pretty expensive sensor.

You will have to rent or borrow a fuel pressure guage. Hook it in line with the fuel line going to the injectors. Then, tape that puppy to the winshield if you have to and drive the car. The pressure at idle should be the same as when you floor it. If you see the pressure drop off at the same time the engine stumbles,then you are looking at a fuel pump issue. If not then I really have to believe it's the mass air flow.

I am not sure on the tps. you should get voltage there. Here is some info I found for testing it. Might help. No voltage should throw a code when you turn the engine on.
626 and MX-6 with 2.2L Engine

1. Remove the air hose from the throttle body.
2. Detach the 3-pin throttle sensor connector.
3. Connect the 49-G018-901 testing harness or equivalent, between the throttle sensor and the wiring harness.
4. Turn the ignition switch ON.
5. Verify the throttle valve is fully closed.
6. Measure the voltage at the black and the red wires of the testing harness using a precision voltmeter with a scale of 0.01 volts, the voltage at the black wire should be approximately 0 volts and the voltage at the red wire should be 4.5-5.5 volts.
7. If the voltage reading is not as specified, check the battery voltage and wiring harness, if these are okay, replace the engine control unit.
8. Record the red wire voltage.
9. Measure the voltage of the blue wire, verify that the blue wire voltage is within specification according to the red wire voltage. For example; if the red wire voltage reading is 4.50-4.59 volts, then the blue wire voltage reading would have to be within 0.37-0.54 volts.
10. Hold the throttle valve fully open.
11. Measure the blue wire voltage, verify that the blue wire voltage is within specification according to that of the red wire voltage. For example; if the red wire voltage reading is 4.50-4.59 volts, then the blue wire voltage reading would have to be within 3.58-4.23 volts.
12. Check that blue wire voltage increases smoothly when opening the throttle valve from closed to fully open.
13. If the throttle sensor does not perform as specified, adjust or replace the sensor.
14. Turn the ignition OFF.
15. Detach the testing harness and reattach the throttle sensor connector.
16. Disconnect the negative battery terminal and depress the brake pedal for at least 5 seconds to eliminate the control unit malfunction memory.