Awhile back my check em=ngine light came on. Got the code and it came back to the EGR. Book says either open circut in EGR temp. sensor, ECM, or EGR valve. I have cleaned and tested the valve by the book and it tests fine. The temp sensor pigtail was changed out by somebody else. Does anybody know if the two wires for the EGR temp sensor can be "mixed up", or reversed, does it matter which is which, ive fliped the connector around, still get the check light. How can i test the sensor or VSV. My truck is a 92 3.0L. Any help would be appriciated. Thanks

Sensor is likely a variable resistance type, varies w/ temperature. A Factory Service Manual might have a chart with some values, or you could check it when cold and hot and see if it changes resistance.

VSV is like a relay for vacuum. Test coil with an ohm meter, probably would be somewhere under 100 ohms. Or apply 12 volts to the coil and listen/feel for a "click". If that is OK, see if the vacuum ports/lines are clogged. Not uncommon for that to happen. To test, use a hand-operated vacuum pump or lacking that, try blowing through the fittings with the VSV on and off. Off should have no flow, on should have flow.

Don't remember the exact setup on the 3VZ but I know on the 22R/RE if the EGR pipe carbons up too badly it will insulate the temp sensor from heating up enough and it will throw the code.

Might look down where it screws in and see if it's carboned shut.

Checked the EGR VSV's, they did click when 12V was applied, vacuum lines seem to be ok also. I did an ohm test on the EGR temp sensor and came up with 131 ohms. Seems pretty high to me, anybody know the paramiters? Thanks.

vacuum lines can seem ok and not work well at all. they get clogged and collapse. They are cheap to swap.