'02 Denali pulsing at high speed

Just changed plugs and wires @ 100k. Now at 102K I'm noticing at 50+ mph, there is a occasionally a slight pulse. No check engine light...no codes. I don't notice the rpm's drop b/c it is so slight and sporadic almost as if it was starving for fuel. If I take my foot off the gas for a sec, seems to go away. Any ideas?

Thanks,
pitt079