I have somewhat the same problem. I have the p0171 lean code. The car sounds like a random misfire but doesn not throw the misfire code. The CEL comes on and off at random times. I have tried changing the plugs and checked all the vaccum lines for leaks. I also returned the car to stock to see if that was the problem and it still does the same thing. I'm at wits end with this problem and have almost given up and going to live with it. If anyone could give some insight into this problem it would be a great help to me.

 

since u didnt list what im gonna write maybe u can try it haha

check or replace o2 sensors

clean MAF ummmm idk what else

and idk if any of these will help haha

 

disconnect the battery and the car should be fine