EGR Valve?

I have a2000 Ford Taurus sel which on start up runs really rough to the point of stalling and also will stall once in awhile while in drive with the brake pressed down while like at a light. But in neutral it will rev low but not stall recent work done includes new plugs, 2 coils, egr valve, 4 02 sensors, and new belt. Please any helpful advice would be appreciated.

A!So the emissions light keeps coming on and it I've noticed it only been doing it worse since the weather has been colder.

OK thanks I will let you know

OK cleaned the iac and replaced 2 coils still running rough on start up acceleration is a little hesitant and emissions light is blinking

Got a diag. Code was "egr low pressure". It also kinda idles rough. I plan on replacing the egr value, pipe and pressure sensor. ANY feedback on this topic is greatly appreciated.

A "clogged" EGR valve could not cause a poor idle, as it's supposed to be closed at idle. Pinging under acceleration, higher operating temperatures maybe. But it would have to be stuck open (or otherwise open when it's not supposed to be, which includes at idle) to cause a poor idle quality.
So, which actual code was this anyway? Because I can't think of any "low pressure" that would relate to the valve itself. It operate on vacuum not pressure. Maybe the pressure sensor, but not the valve.
If we had the actual code, maybe someone who knows what's what could clear this up, and save you a lot of money wasted on perfectly good parts being replaced?

My engine light came on and I took it to get looked at by my local mechanic. He said the problem was most likely had something to do with the EGR valve. I was wondering if I dont get it fixed right away, what kind, if any, problems come along with this.

My engine light is on and I read the code, the code was p0401 it is egr insufficant flow, I was woundering what that could be if it is a egr vavle problem of vacum problem

Engine problem
1999 Ford Taurus V6 Two Wheel Drive Automatic 14339 miles

I have two questions really. One is my car when first started in the mornings or after a period of over eight hours not running will stall out multiple times before running well. Someone told me EGR valve but I disconnected that and still have same problem when hooked up the car gets horrible gas mileage. Any advice? Also when looking under my hood to winterize my car I do not find a radiator just an overflow jug. Does this mean I use dexcool or what sort of antifreeze?