I have an 89 PU w/ a 22RE. My truck runs flawless except it idles rough and almost sounds like it's missing a bit at an idle. 150K on motor. Any suggestions to smooth out my idle?

 

my 87 did the same thing for a long time. Checked vacuum lines, 3 were bad, helped a lot, but still was rough. Replaced Upper and lower intake gaskets, the lower was leaking and that helped out A TON. Also while we were in there we put a new egr valve in, might have aided a little bit.