Testing your TPS is a great starting point if you’re experiencing a hunting, searching, or surging idle, hesitations, lack of power, or general rough running. At the age/amount of use most of them are now at, they’re very prone to failing or having dead spots in their range of movement. The testing procedure is simple and doesn’t take much time, and should be part of a good yearly routine maintenance schedule.
With the car completely warmed up and the engine off, unplug the TPS connector then set your multimeter to test for resistance.
Connecting between terminals A and B, you should find 1K ohms with the throttle in the idle position, untouched. Opening the throttle completely, you should have 5K ohms, plus or minus 1K.
Checking between terminals A and C, you should find 5K ohms, plus or minus 1K, in both the idle and wide open throttle positions.
If you don’t find 1K ohms between terminals A and B in the idle position, turn the flat-head screw found on the arm touching the TPS until you’re very close to or at 1,000 ohms. After doing so, it’s not a bad idea to open the throttle by hand and let it close by itself, then re-set the TPS resistance. Repeat this procedure until it consistently winds up within 20 ohms of 1K.