So with engine idling, run an UNLIT propane torch up and down the vacuum line from booster to plenum. Or use a little ether or carb cleaner, spray the line in the same way. An idle up tells you there's a vac leak. Replace hose if needed. Adjusting timing and TPS may also help to correct your issues. If they're far enough out of spec, sometimes similar symptoms will be noticed. You might pull and clean or replace the temp sensor as well. It is unrelated to your gauge sender.

 

Those two vacuum line you hold with the screws are part of the AC idle up and powersteering idle up.

There are two more hoses like them connected to a simular outlet below those that runs under the the upper intake manifold and around the front over the timing belt cover, From ther it goes through part of the SRS after the airflowmeter.

If you have AC, The AC is turned on it activates the GREY VSV on the passenger fender, There is a knob that adust how much to idle up.

Powersteering idle up (All models)
The power stering idle main valve comes out the bottom left of the PS pump, It help idle up the engine (mainly during idle) so not to stall while turning the steering wheel.

The reason they end in a line connecting after the AFM is so is measures the air passing through the idle up section fueling the engine.

 

Would that make it idle up an down when on the brakes?

 

I read this on another forum awhile back. Have you checked your idle setting? The reason I ask is if the idle is to high then the computer will (as quoted) will engage/disengage causing a fuel cut when applying brakes.

Maybe this can help. I would take out the idle air screw clean it and replace o-ring and adjust idle 850 rpm +/- 50 . Good luck

EDIT: I watched your video and it seems like your idle may be to high especially that you don't have a tach for reference.

 

Similar issue on my 92 22RE. Newer O2 sensor, new thermostat, new coolant temp sensor, new MAF. No known vacuum leaks. Coolant level normal. Only surges while on the brakes.
Weird. Lots of threads here but no definitive fixes.

 

I get back in town Friday an see what I can do hopefully its just a vac leak

 

TPS in spec? Timing right on?

 

same deal. 89 3.0 v6

damndest thing is it starts acting up whenever I'm in a drivethru

 

Sounds like a bad brake booster.