Need to know were the throttle sensor unit is located

Your 2000 Frontier only has the one TPS sensor.

no country told. a tall, and makes parts, and service data super hard to get and helpers help.
NO YEAR car, (sad face) 1997 present.
well there can be 1 or 2 sensors there or even 4, on newer cars
old cars has a cable drive throttle. and 1 TPS sensor..
tick tick evolution: happens. and....
then the newer cars. are TWB Throttle By Wire.2003 up.
2 pedals sensors and 2 TV sensors and motor drive throttle body
the TV is the throttle valve, on top of engine connected to the air cleaner but wait, no year no engine told.
sorry we cannot guess 5 engines or the year;

1.3 L Family 1 I4 (gasoline)
1.5 L Family 1 I4 (gasoline)
1.6 L Family 1 I4 (gasoline)
1.8 L Family II I4 (gasoline)
2.0 L Family II I4 (gasoline)
TO fix any care DIY, learn what is under the hood first or help is useless. like mine.

this is the throttle sensor the air intake feed come into this, its different on some models, part number is on the unit match part number with replacement.

It tells the computer the angle of the throttle. how far you have the pedal down.

The throttle plate is located inside the TAC unit. It is square, made of aluminum, has one electrical harness and one vacuum line going to it, and is on the top of the engine. It is bolted to the plenum and is in-line between the MAF sensor and the Plenum. If I can be of more help please let me know.

Hi, we need you know your model, year and engine to be specific. I have some generic tips here: Please see my tip at http://www.fixya.com/cars/r7427423-fix_poor_idle_high_idle_stalling_fuel . These are generic instructions. If you getstuck or need specific instructions for your car, please get back to me with model, year and engine info.

Thank you. There seems to be a problem with your mixture of gas and air. This can be caused by a lot of things, and I may need additional information, (e.g. is the check engine light on?) I would have the following sensors checked. The Manifold Absolute Pressure Sensor, (MAP), located at the opposite end of throttle body from air intake. the Coolant Temperature Sensor (my guess with info on hand), located at the end of the engine away from the belt, the O2 Sensor, located IN the exhaust manifold, and the Fuel Pressure Regulator. The Throttle Positioning Sensor does not control mixture, it just tells the computer where the peddle is so it knows how much fuel to inject. I hope this helps. IF your C/E light is on, take it to Autozone etc, and get your codes FREE. Let me know what the codes are if you need more help, just ASK! Thanks for calling FixYa.com Don't forget to rate this advise.

passenger side behind the starter

P0121 - Throttle/Pedal Position Sensor/Switch A Circuit Range/Performance Problem

The throttle position sensor is probably either damaged, dirty, unplugged, or dead. It's located on the engine. Find the throttle body - the TPS will be the little box on the side of the throttle body - it measures how far open the throttle is, and tells the computer so the computer knows how to direct the car's driving parameters (shift points, fueling, etc).

The temp sensor known as the engine coolant temp. sensor tells the computer if the engine is overheating and so forth and tells the injectors how much fuel to give the engine. The temp. sending unit is what controls what your guage reads. It sounds like you need the temp. sending unit. It located near the thermostat housing with a single pole connector.