CosmoCoffee

I've added the equation of state, and the effective sound speed of dark energy to cosmomc, and the results were as I expected so I'm confident it is running correctly. However some of my 2D plots have very bumpy contours, especially the contour plot of w against sound speed, i.e. not smooth contours like omegav against omegam. Is there anything that can be done, perhaps in the distparams.ini or params.ini files to sort out this bumpiness?

You can increase the bin size, but then of course contour locations may be less accurate. Otherwise you just need more (or better) samples.