Rochester Varajet Throttle Position Sensor 1300-3

What the TPS Does:

• Monitors the position of the throttle blade in real time

• Sends a voltage signal to the ECU that varies with throttle opening

• Helps the ECU control:

  • Fuel injection

  • Ignition timing

  • Transmission shift points (on automatics)

  • Idle speed and fuel mixture

What Are the Symptoms of a Bad TPS:

• Jerky or hesitant acceleration

• Engine stalls or idles rough

• Poor fuel economy

• Check Engine Light (CEL) comes on

• Transmission shifts oddly or erratically

 How Does a TPS Work:

• The TPS is mounted on the throttle body, directly connected to the throttle shaft.

• It uses a potentiometer (or sometimes a Hall-effect sensor) to measure throttle angle.

• As the throttle opens, the voltage increases (usually from 0.5V closed to 4.5V wide open).

• The ECU reads this signal and adjusts fuel and timing accordingly.
  

  Frequently Asked Questions – Varajet TPS 1300-3

  1. Which carburetors use the 1300-3 TPS?
  This TPS fits the Rochester Varajet (“Varajet II”) carburetor.

  2. What is the function of this TPS?
  It continuously monitors throttle blade position and sends a variable voltage signal to the ECU or controller. This helps regulate fuel delivery, ignition timing, transmission shifts, and idle control

  3. What symptoms indicate a bad TPS?

  • Jerky or hesitant acceleration

  • Rough or unstable idle

  • Engine stalling

  • Poor fuel economy

  • Check Engine Light (CEL) illumination

  • Erratic transmission shifts on automatics

  4. What are the OE part numbers this replaces?
  This unit replaces GM numbers 17067587, 17068612, 17078516, and 17078578

  5. Is this TPS still in stock?
  Yes – current availability shows "In Stock", and orders placed before the cutoff typically ship the same day

  6. Is it returnable if I accidentally order the wrong part?
  No — electrical components like TPS sensors are final sale and cannot be returned due to calibration sensitivity.

  7. Can I test the TPS at home?
  You can test by measuring output voltage with a multimeter while slowly opening the throttle. Voltage should move smoothly from ~0.5?V (closed) to ~4.5?V (wide open). No output variation or dead zones means the TPS is likely bad

  8. What's the price and where do I buy it?
  Priced at $22.95, you can purchase it directly from our site. Availability and pricing are real-time.

  9. How is shipping handled?
  Shipping rates are calculated at checkout based on your address and selected method. No hidden fees apply.

  Tip: If your Varajet-equipped engine shows shift issues or rough idle under load, a failing TPS is often the culprit. Replacing it can restore smooth throttle and transmission performance.