Tranny Issue
 

If I keep a steady throttle going about 45 at 1600rpm in 3rd gear every once in while it will flare up for a half second or so like it is slipping. It will only flare up a couple hundred rpm's, then go back to how it was running before. I had the gov pressure solenoid changed twice and this did not help and also did not get rid of my 1-2 shift hunt. Does anybody have any ideas what is wrong.

Stock tranny?

Yes totally stock tranny.

Gov. pressure sensor?

Just for the heck of it, overfill with a pint of ARF. I fought this one for quite a while. Seems was picking up air and losing pressure.
Also check brake switch. It will cause unlocking of torque converter without warning.
There is a bulletin on upgraded gov pres solenoid or transducer for reducing low speed 1 - 2 hunting. Didn't fix mine though. Gave up and drive through the issue. Make sure throttle pressure cable is properlly adjusted. Sometimes just .010 off will mess things up on shifting.

If you have not done any trans work, your tires are the cause. What you are seeing is the symptoms of mismatching the drive train components. At 45 mph with those tires its on the verge of 2-3 shift hunt all the time. Your lucky it doesn't do it constantly.

Since you already have the 1-2 hunt problem, a shift enhancer would be a good start on a cure. FYI, consider a shift kit also. Those tires and stock trans pressures are really hard on the direct clutches.