2000 Subaru Outback 2.5 l. base engine, Po130

Question

Got codes Po130, Po301, Po302 with CEL on for past few months. I had notriced misfirinf recently on damp mornings. Mechanic replaced coil, which was arcing to wires, as well as the wires and plugs. (Car has 150K miles, wires never replaced, plus last replaced 80K mioles ago.) CEL and codes were cleared.
Now all looks fine for past 50 miles after fix, and car runs really smooth with plenty of power! However, I had ordered the IAT/MAP sensor from an online parts store, since I figured this would have to be replaced in any event and I can easily do this install.
Another intermittent problem I have had for years is the strong smell of gas on very hot or very cold days -- it comes and goes. I read on another forum that this could be related to a faulty IAT/MAP sensor.
SO...Should I send back the sensor and try to get a refund, or put in the new IAT/MAP? It only cost me $100.