"Rough" Idle

200 miles on the lower intake manifold gasket repair on my 2002 Blazer (199,400 miles). No coolant leaks, no oil consumption (three changes to clean up the coolant/oil). New rotor and cap. Compression good. Idle, acceleration, power are all strong and steady. The idle does not hunt or falter but it is not smooth. It's kinda grumbly. Rough but very steady.

I will check the vacuum but I normally associate vacuum leaks with other problems. Never touched the fuel injectors. Did a fuel pump at 100,000. What should I look at? One thing I have never done is motor mounts, never owned a truck long enough. Could that be it?

Thanks,

George