Ford Aerostar :: 1994 - Temp Gauge Reading Low?

It is a garage queen 1994 4.0 AWD with 42,000 miles in nearly perfect shape. Except for the dent in the rear on the passenger side.

I have posted a picture of the dash when going down the road. As you see the engine light is on. It comes on intermittently, pulled the codes, indicated MAF, 02 sensor, running lean/rich. Runs like a champ, no hesitation, still gets up and goes, gets the appropriate gas mileage. I replaced the 02 sensor with the original Ford Part. Didn't cause the engine light to stop going on after about 20 to 60 minutes driving, sometimes it doesn't come on at all.

Could this thermostat be running too cool and causing the engine to throw those codes? Would gladly take it to a mechanic, but seems like it might be a fishing trip with my dollars for them. Next I was going to replace the MAS myself, easily done with the original remanufactured part at a cost of 150.00, 70 for the core, but don't want to chase my tail with these engine lights on when it runs nearly perfect.

Have sprayed the MAF. Checked for air leaks anywhere. Done all the things I could do by just lifting the hood.

So the picture shows the Temp gauge barely touching the N flying down the road at 70 on a level surface, outside temp about 60. Reading the posts says they all run in the cool section of the temp gauge.

So the question is, do they run this cool? Heater works fine and the gauge goes up past the N resting before the O when going up hills on the way to Tahoe. Is this a thermostat problem on a 20 year vehicle with low mileage, or am I going to have to bite the bullet and let the mechanic go wandering through the vehicle?