P0302 & P0300 codes
 

So there was no build up to the the cyl 2 misfire, it just started.

I have a 2009 base 370 sitting at ~70,000 miles with the only mod being an axle back exhaust.

I have up to this point replace the spark plugs and the ignition coil and no luck with the misfire. I've used a multimeter and probed the harness going into the coil and I'm reading ~12v, although this only proves that the harness isn't damaged. As well I've had a listen to the injector and its fine. I've read that it could be the camshaft position sensor so I took a resistance reading of both and on one I read 10.3MOhms, which seems a bit excessive, and the other one I was unable to get a reading (could be a problem with me, I didn't have a lot of time to check). Also as a side note, when I first crank my car I can smell exhaust fumes inside the cabin but this is more recent than the mis and could be unrelated. Also the only tools I really have access to is a code reader and a multimeter. Any advice would be appreciated .

First thing I'd do is clean the MAFs. It's possible they're the problem and it's a quick/easy/cheap job. You might want to clean the TBs, also. Several threads on both jobs are on this site.

Sorry, forgot to mention the TBs are clean(First thing I did). Ill double check the MAFs but I did looked them over but didn't see anything but it wont hurt to clean them. In the event that cleaning doesn't work (probably not knowing my luck) anything else I should be on the lookout for? I've seen some instances of the ECM failing (same symptoms I have), how real of a possibility is that?

You listed a PO300, which is a random misfire code...low fuel pressure can also set these codes.

ECMs seem to be very reliable but it's a possibility. Could be a dirty/bad injector. As per jchammond, it could be fuel pressure.

Got the same misfire from cylinder 2 as well. In the process of installing new sparkplugs and hopefully that fix's it. If you find out what the problem is, please let me know. Good luck!

P0300 is nearly always a vacuum leak or air intake leak.

When troubleshooting a misfire, the best starting point is to use an OBD scanner and look at your long and short term fuel trims.

Also, look at the mode $06 data, as it has misfire counters and you can get a sense if it is common to a cylinder bank. OBD Fusion has a very good diagnostic report that shows all this data.

You might want to also pull the plugs and see if they are all the same.