03 350z jerking back and forth, low rpm idle
 

Hello 350z owners! I have my 03 350z that has been causing me issues lately. I fixed an overheating problem recently with a new water pump and thermostat. I'm now running into a p0300 code. Random misfire, but I just changed the spark plugs and ignition coils. Also crank and cam sensors. What is happening is slower acceleration and its popping pretty bad. And then it eventually stops accelerating while my foot is on the gas. It slows down. And then I'll try to shift in a lower gear and itll start bogging and itll jerk the car forward at a slow tempo to a point you cant accelerate over 15 mph in first gear. At that point even in neutral the car wont rev. Itll make that same bap bap bap slow jerking sound. I need help. I'm thinking fuel pump is bad and fuel injectors since it's still reading a misfire code. SMS HELP!!!

Could be the crank position sensor. Sounds like the car is going into limp mode. Do any clutch work recently? What, if any, aftermarket mods have you or previous owners done?
-Icer