[akorna]

Been troubleshooting an intermittant miss at idle - '99 Cherokee 4.0 Auto 4X4. My OBD II scanner shows that the TPS is sending a signal of 15% throttle opening at idle (even though I'm not pressing on the throttle). Signal voltage form the TPS with the ignition off is 0.78 votls (within the 0.26-0.95 volt range. Shouldn't the TPS show 0% throttle if you're not pressing in the throttle?

Anybody else show more than 0% at idle?

Thanks!

	Throttle position sensor A throttle position sensor (TPS) is a sensor used to monitor the position of the throttle in an internal combustion engine. The sensor is usually located on the butterfly spindle so that it can directly monitor the position of the butterfly throttle valve. The sensor is usually a potentiometer and therefore provides a variable resistance dependent upon the position of the butterfly valve (and hence throttle position). The sensor signal is used by the Engine Control Unit (ECU) as an input to its control system. The ignition timing and fuel injection timing (and potentially other parameters) are altered depending upon the position of the throttle, and also depending on the rate of change of that position. For example, in fuel injected engines, in order to avoid stalling, extra fuel may be injected if the throttle is opened rapidly (mimicking the accelerator pump of carburetor systems).