2001 voyager hesitates.

Hi all. I have a 2001 vouager with 79000 miles. On mornings when I start and drive before warming up properly the van kinna hesitates and sounds like it misses a little. When it is warm it works just fine. I reciently changed the sparkplugs and air filter and engine oil before I took it for inspection. I did not change the spark plug wires but I doubt that is the reason cause it works fine while hot. I just changed the transmission fluid.
Any ideas would be helpful. Thanks

Check the EGR valve and oxygen senser. If the spark plug wires are original they could be the cause.

I'll look into this. Would putting a code tester on it help even though I don't have a check engine light on? Also, not to sound like a moron, but what is the EGR Valve?

Also, This is my first time owning a kind of new car. My last one was a 1996 caravan. Does anyone know what is the standard warranty and where I can find out what is covered by the drive train warranty? i read somewhere that it is supposed to be 7 years or 100000 miles.
Tks