Noluck here. 2002 Altima engine light and misfire . Everything has been checked. Dealer said ECU had to be replaced which was done. Still have light problem and misfire problem.
Now Nissan says it is the TCU that is sending mixed signals to ECU and that needs to be replaced. Makes no sense to me. Is this possible.? I think they are trying to cover up
Misdiagnosis of bad ECU.

Have you replaced spark plugs with the exact ones that came in the car? Are they gapped to specs? Have you replaced the coil(s)? Did you use dielectric grease on the plugs?

just finshed working on a 02 altiama with the same problem po300 random misfire detected.. finally change the knock sensor on the back of the engin right under intake on block worked find price is around 135.00

just finshed working on a 02 altiama with the same problem po300 random misfire detected.. finaly change the knock sensor on the back of the engin right under intake on block worked find price is around 135.00

Did this info help I'm curious