2002 Nissan Altima Random Misfires

Power/Fuel
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1

2002 Nissan Altima, 85k miles. Lately, about every few weeks, I get a misfire on cylinder 1 on a cold start. After a few seconds, it smooths itself out and operates normally. This morning, the same happened, but it was cylinder 3 instead (I use a smartphone OBD2 reader. Not sure if it matters, but the exhaust manifold/precat was replaced about 1k miles ago (to avoid the infamous pre-cat failure in this year model)

This car has been great! What the heck? lol

2

P0300 2002 NISSAN ALTIMA SEDAN Code Cylinder Misfire Detected Random Cylinders (autocodes.com)

3

Misfire Due to Faulty Intake Manifold : Nissan Altima Engine (repairpal.com)

4

Except it didnt throw out P0300, it threw out P0301 and then P0303 on separate days. Or does that make a difference?

5

po301 is for cylinder 1 misfire and po303 is for cylinder 3 misfire

6

Yes I realize that. I guess what I am asking is what could cause a misfire on two separate cylinders on two separate occasions? And in both cases, the car smoothes out after a few seconds and operates normally.