I want to thank all the respondents above for their replies. I just finished the testing of a new ECT sensor I just removed from my engine. Read correctly to 600ohms then started jumping to 1800 1900 back to 500 then 1600...well, all over the ohms field as the temp was rising above 196 deg (water temp). So as expected it was a bad new (but cheap) Brand->Standard T-series part, made in Mexico! I put in an old ECT sensor ( NAPA-Echlin) Made in the USA and everything is running fine now. I thought perhaps it was the connector or a short in the wiring that was causing the engine idle and gauge problems I was having. Having test driven the car 30 miles or so, all is back to normal. Your input did help me and I am sure I will need help again someday.