When the engine is first started it is in open-loop mode. This ignores correction data from the O2's until they warm up to operating temperature.
You have a mixture problem which is mostly corrected when running closed-loop. Clean the MAF and check for air leaks. Common air leaks are vacuum lines including the hose on the PCV valve, the fresh air line from the valve cover to the intake tube, an open oil cap or dipstick, connections between parts of the induction system...
Timing belt and fuel pressure may be causing this.
Poor spark and bad engine mounts will make the roughness worse.
