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