it may be a bad torque converter.
the rear brakes are grabbing. the linings may have fluid on them from wheel cylinder leak or dust buildup. sanding the shoes may help .
If by surge you mean the batterys volts drop and the engines rpms drop all the vehicles accessories that are on at the time are wanting to draw more amps then the vehicles alternator has to give. or by surge you mean the rpms increase a little bit and if the heat or A/C is on at the same time the A/C pump or clutch might possibly be going out.
the rpms should rise and then drop no more then 500 rpms when the fan on the radiator turns on and then off.
If your 1992 Voyager does not seem to drop into the proper RPMs so that you are running at 5000 RPMs at 65 miles per hour, the timing belt might need adjusted. It can also indicate the idle is set too high.
If the rpms are to high for to long the engin will over heat and you will drop it
Try replacing the map sensor
This is a sign that you need to have the brakes inspected, soon. Worn brakes causes the brake fluid reservoir level to drop causing the brake and abs lights to come on.
The A/C puts an extra load on the engine, so it's natural that the engine RPMs drop slightly when the A/C is activated.
is it an auto? it sounds like if its an auto that the troque converter clutch is sticking and acting like a clutch in a manual trans when this happens its like never pushing in the clutch till the last second which causes it to nearly stall hence the drop in rpms and voltmeter readings as the battery attempts to keep motor running
A wall cloud marks an area of low pressure within a mesocyclone. The pressure drop causes a temperature drop, which in turn causes water vapr to condense.
If it is the SRT model it is probably the turbo, if not it may be the transmission