I just found the trouble... the EGR valve was set up with carbon. I applied some vacuum to it and it "popped", now the car is running beautifully. Now I have to clean it out and it should be okay for a while.
At least, when it happens again, I will know what to look for, and hopefully will have the funds to replace it.
BTW... my plugs and wires were replaced about 3 months ago.
Thanks for your reply!