92 Roadmaster Estate Wagon 5.7 TBI engine temp

[ulremember]

Hello to all, I have a engine temp question
I have the above mentioned vehicle and noticed that the temp normally stays in the 120-140 deg range. Now, I had to travel our Grapevine here in Cali a few weeks ago during our heatwave. The temp went up to about 200-210 (if gauge is accurate) and she cooled down very well after the steep grade.
I do notice that "she" is running a bit rich by the odor from the exhaust. Could it be that the ect is going bad? I had a Suburban with a 454 TBI with the same odor and POOR fuel mileage. Once changed, it was much better. Does anyone think that I should change the ect? Or does anyone have the ohm specs for proper operation of the ect?
Also, I noticed a past post that says you can get the engine operating temp from the AC control unit, but the link was bad.
Blessings to all that have read!
Chuck aka ulremember