Truck has been running great but today started acting up at idle. Not much but the idle was fluctuating ever so slightly which is unusual for my rig now with EBL. I parked up at home and just as I was about to switch off the idle climbed to around 1500 or so rpm for a couple of seconds and then went into limp home mode, throwing an SES light.
I switched off and then restarted after looking around in the engine bay and it did exactly the same. I pulled a code 21 .

So...does this sound simply like a bad TPS or is there more to the story?

 

This isn't DIY-PROM related, but why not hook up a voltmeter to the sensor and check that its range is valid? Code 21 indicates high, so check that it goes up to about 4.5 volts on the output. Or hook up a scanner and let it tell you what the voltage range is. If in doubt, replace it. Then move on to the next potential cause (i.e. other codes, etc) until the problem is solved.

 

OK thanks.