throttle position sensor troubles

I have a 95 chevy s10 blazer that is idling way to high and shifting at 3000 rpms. i replaced the throttle position sensor three time and took it to a mechanic friend that says the sensor is getting no power. he changed the computer and a wiring plug and it still didn't fix the problem.
it also needs a starter and battery and alternator could these be the source of the problem or is there anyone out there that knows what this could be? Any suggestions would be appreciated. please help!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!!!!!!!!1

get a book on the truck and see where the lines from the sensor tie into the ecm. then you can run wires into the plug of the sensor and over to the ecm and hook it up to where the wires from the wiring harness is supposed to go. you might have a broken wire. make sure you check your wiring for the test and then make sure the ecm's off while your doing all this.

I just sold my 87 4.3 G-20 van. I had the same problem and no one could figure it out. TPS, computer, new TBI system than new motor and it still did it. One thing you can check is the base gasket under the throtle body or look for a vacumn leak. Could be a cracked hose.

sounds like a vacuum leak to me.