Altima 1994

Light normal but when it turns it off this is on

It seems that you have a piston or bell, (the fuel is self -consideration) Possibly the combustion camera has carbon deposits that are lit when you turn off the engine and bise on the fuel. This is the same that happens when we lower the octane requirement of a vehicle

It happens to me, it also occurs when the chain or strap is not well synchronized.
Greetings

This has to be electronic injection and preignation problems happen only in carbureted vehicles. The safest thing is that the cooling fans have put directly, if so, it is most likely that a few seconds are on and turn off. You have to check if the food that the fans have is direct from Ignition and not with a relay if it is direct, the fan generates a voltage when turning off the contact and turns off when the fan stops.

It would be important that you give us the data of which fuel you use and if you have made any electrical installation lately, sometimes the cables of the day or alarm or some other component are pinllated