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STP and gas mileage

I have a 1990 Nissan Maxima with 136000 miles. Will putting STP or something like it in the tank with a fill-up help it run better or help get better gas mileage? As you can tell I’m pretty much of a dunce with cars.

If you have symptoms of clogged fuel injectors (hesitation, rough idle), adding a quality fuel system cleaning product like Seafoam or Chevron’s Techron will help those symptoms and may help to increase your gas mileage a bit. STP fuel system cleaner is essentially useless.

I would agree with the above. Also, under no circumstances, put the sticky STP engine treatment in you crankcase. That’s for very old, worn out engines that use oil to get a few moreextar miles before they bite the dust.

Do as these folks say. There are additives to clean your car, which might get it running better and thereby return mileage to normal, but there are not miracles in a bottle that will significantly increase the mileage of a good-running car.