You need to be ruthlessly methodical about this. If you throw random parts at it you'll never get it fixed. Engine not responding to throttle if the butterfly valve is moving in the throttle body could be a problem with fuel, or compression, which is easier to check. Does the engine stall? If so, spark could be the problem too.
Are you seeing a check engine light?
Don't the throttle bodies have to be paired to the ECU for proper idle speed? Replacing that would have been a LAST resort in my book, after replacing the fuel injector, but even that would be pretty far down the list.
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