Acceleration Issue

Good day all!  I've got a 2000 Taurus with about 125K.  Over the last couple of weeks, I've noticed that when I climb a large hill (daily) with cruise set at 55/60 the car has a "mushy or miss" accelaration.  Also, after I feel it the rpms increase to meet the demand of the climb the "mushy/miss" acceleration is gone.  It reurns when the rpms level out again.  Today I encountered it again and half way up thye hill, the check engine light started flashing and kept flashing until I leveled out.  Went out ans stayed out for the rest of the trip.  Otherwise, the car works as advertised.  Recent maint:  oil change, fuel filter, egr/pcv valve/sensor.  
 
I'm not the sharpest bulb on the tree but could it be the plugs/wires or transmission slipping.   I'm not the first owner so I don't know if there was a tuneup done.
 
Any point in the right direction is appreciated.
 
Golferguy

check your vacum lines to see if one is bad or put a vac gauge on and check vac.  kinda sounds like a possible bad vac.

If the CEL came on and was flashing, there is a code stored. Get a scan and post the codes here.