My question is that my idle at start-up goes up and down for about 10 sec. And then stabilizes-also sporadically at stops the idle will be so rough and at time is smoother, it shakes the car-I have replaced the plugs, wires, coil pack, and replaced a used tested transmission-also the idle control valve is not operating(I took it off the car and there was no spinning evident)-also I have just reset the valve cover gasket and the engine rocker cover still leaks slightly-I secured it very aggressively-could this possibly cause the leak?
Uneven tightening of the valve cover can result in leakages. A bad gasket could also be the cause. If the leak is from around the arches of the cam holders, that could be because no sealant was applied or not applied evenly.
If the IAC is not operating, it would cause idling problems. Surging are usually due to idling speed excessively high.