so I have a JDM legacy with an EJ205 swapped in. I had a low baromatric pressure engine code. A mechanic and he told me to replace the MAP sensor, so I ordered one on ebay (part #22627AA170) for 50 bucks. Today I received the replacement. It doesn't have the Denso sticker on it, so I'm afraid it might not be a genuine part, but I figure it should still work. I verified that this was definitely the correct part number (same as the one on the sticker on the old, presumably bad MAP sensor).
Until today, the car was running fine. The idle is maybe a little harsh (it fluctuates a little), but I was driving the car around town with no problems. It idled around 800 rpm. it's a PITA to get the MAP sensor out because it's underneath the IACV, but I got it out and plugged in the new MAP sensor (sadly the nipple broke off the old one on the way out). I unplugged the battery for 45 mins and started it up and it idled extremely high at 1500 rpm with white smoke coming out the exhaust, smelling strongly of gas. When I revved it, it kinda sputtered and the rpms would drop, but then it wouldn't hold an idle. Now it only starts if I give it gas and it still idles at 1500 rpm with a lot of white smoke. I don't want to start it anymore. I'm afraid I've already damaged the engine.
Maybe there was some underlying problem, but all I did was change the MAP sensor, and it was running +/- fine before. I didn't touch anything else. I would plug the old MAP sensor back in, but like I said, it's broken. I guess I am going to order an expensive OEM MAP sensor from Subaru, but I am just confused: What the hell could have happened?