The temperature reading may just be the coolant temperature sensor is knackered and needs replacing.
If your idle is erratic with a new MAF plugged in then somewhere between your MAF and MAP the ecu recognises that there's a leak because of the change in reading between the two. Either you have a boost leak, a diverter valve recirculation leak or a vacuum leak. If however it's always been erratic and been getting gradually worse then it might just be a dirty throttle body/IAT sensor in which case a good clean will some carb bleaner will fix this.
If the problem started ever since you've installed the new MAF sensor then try disconnecting the battery for a few minutes, then put the terminal back on and see if that helps, because it can also be the case that when your MAF was gone, the ecu also recognised this and logged an error, this would have put the ecu on a fail-safe setup and fuel will be adjusted from your lambda sensor, but when you plugged the new MAF back on it may be that the error is still logged. Taking the battery terminal off for a few minutes will help clear any errors logged. Try this and see if it helps, if not then maybe try a smoke test to look for leaks.
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