My 95 Maxima has started to shake roughly while it is in Park and Drive, but more so when it's in Drive. When it's in neutral its fine, but once I put it back in drive the problems begin to arise. So far I changed all of the spark plugs and ignition coils. But for some reason, I'm thinking it is this aftermarket mass air flow sensor I got off of Amazon. I don't really know, but I'm open to any help/ advice.

Link to AfterMarket Mass Air Flow Sensor:

 

I'm having the same problem and I have the p0150 code (front o2 sensor). I'm replacing it early next week. I'd get your codes checked to see what the ECU knows.

 

I had that same code earlier this week, but I had that resolved when I changed my front upstream O2 Sensor.

 

I world check the fuel injectors. It sounds like an o-ring failure. Fuel would be leaking into the cylinder.