what is this check engine light code mean? 94 ford mustang,?

It likely means that there is air entering the intake system before the Throttle and after the MAF, so the values are different and it is making the ECU think there is a difference in air values from the MAF to the Throttle body. I would have your intake system smoked tested to check for any leaks and go from there. If you are in need of parts for your vehicle, check us out at:

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Hope this helps, Good Luck!

First check the vacuum lines for an air leak. There may not be a problem with any of the sensors, but the software has detected an abnormal difference in air flow in relation to throttle position.