Driveability problem

[exgmguy]

I must have aged over the winter because little thing lke this did not bother me last year. Anyway, My car has a slight bucking or surging problem when cruising in gear. It runs like a raped ape when I am on the gas, but at cruising speeds it acts up a little, and when I use the engine as a brake even as low as 2200 RPM it pops out of the exhaust more than before. The car also smells pretty strong of exhaust.
I am guessing that I am running too rich off idle for some reason.

The only change I have made to the car since before the problem was switching from a GT-40 intake to a Holley Systemax.

Thanks,

Rob