This is what I was told when my 96 did the same thing. It usually did it at highway speed. The check engine light always comes on... "The computer automatically turns that check engine light on. After so many starting cycles it will disappear or there is a way to reset your computer. As far as Autozone, well I trust them about as far as I could throw them. Go to a reputable shop and they can put a analizer on and tell you if you have a problem. If the truck runs fine, dont worry about it. It will go off, unless there is a problem and you can tell it. This is usually an emmisions problem, especially if the truck runs great. I just fixed mine. Auto Zone put a code reader on it, found #4 misfire (I think P0304) code. If you look at page 6 I posted my answer. My intake manifold ports from EGR had clogged. The 96' was last year of the filthy exhaust gas recirculation idea for most cars."
under your air filter
lets warm air in when it reaches a certain temperature.
The intake air temperature sensor is built into the MAF sensor on a 1991 Nissan pickup. It is between the air box and the throttle body.
yes
no
no
It seems that your thermostat is not opening.
sounds like a temperature sensor problem
temperature sensor.
in the gas tank, it is part of the fuel level sensor
below the raditor hose that's connected to the thermostat.
The right type of fluid will keep a car running at its best. The 1995 5-speed Nissan pickup uses 75W-90 Gear oil.