Engine noise near left side of engine

So there is no signs? I am not sure if the noise is coming from under the valve cover or behind the power steering pump. The car is running rough on an idle. It seems to run ok at highway speed. Only thing the engine noise is there at an idle an highway speeds ( louder on gear changes). If I do take the valve cover off. How hard is it to put back on? Also, if the chain is loose can a novice mechanic (I have worked on my cars doing brake jobs, replacing starters, and one head gasket job) replace it or am I out of my league? I just do not want to replace a timing chain and still have a crappy running car. One last thing - can a bad alternator produce the problems I am taking about? The alternator is on the passenger side under the power steering pump and the sound may be coming from there.

Also, I did take it to a mechanic to make it run better. They replaced the spark plugs, wires and some kind of an electrical box. It ran slightly better but I think I was taken for a ride on the repair. It definitely was not the solution to the problem of the car running crappy.

So when I pull the valve cover what am I looking for in terms of the timing chain? How will I know if something is out of whack? Also, what equipment do I need to do a compression test?

Anything on what I should be looking for with the timing chain? How do I know it is out of whack? Also, what equipment would I need for the compression test?

Also, when I rev up the engine there is a clanking noise. I does sound like something baning into something else on the left side of the engine. So to take the engine head cover off do I just undo the to star bolts on top. Is there anything else to loosen?

It sounds like a clanking knocking noise. Especially when I rev the engine or when I drive it and I am accelerating. I guess it makes the chain swing under the cover and hit it or the chain guard. I will look for the model. Where can I find it out?

The valve cover is silver with two black torx bolts (one on each side). The spark plugs angle towards the front of the car. The car is a four door sedan. The car came with the owners manual for a S-Series. As for the clanking noise, it is present all the time but much more noticeable when you throttle the engine. It is coming from the passenger side of the engine. When you drive the car it runs rough on an idle and smooths out when you are driving at highway speeds. The noise is noticeable on acceleration. Should I do something to test for the rod knock before pulling the valve cover. Also, if I pull the valve cover does it come off easily after I loosen the black torx bolts or do I have to pry it up carefully?

I disconnected each spark plug wire as you instructed and there was no change to the knocking noise when I throttled the engine. It seems that the noise is not really present at an idle but the engine runs a little rough. When I throttle the engine, like I said before, there is a knocking noise ( like someone is taking a small hammer and tapping on the passenger side of the engine). I did not pull the engine cover yet. Any other thoughts before I move to this step?

Also, what does a map sensor look like. You said there are two 10 mm bolts I need to remove on that part.

I took off the valve cover. As far as I can tell the timing chain looks tight. Looking at the valves- the valves on the passenger side look dark with some dark oil buildup ( not extreme). The valves on the drivers side look clean and have a gold look to them. Does his tell you anything?

It is my daughters car so I did catch it low sometimes. If it is rod knock is there anything that can be done to fix it? Also, is there any tricks to put back a valve cover. The gasket looks like it will be challenging to line up. Can I use silicone with the gasket to "glue it to the cover" and then put the cover back on. Lastly, if I use the silicone is there a special type I should use " high temperature" or something?

It is rubber. I was going to use the silicone to just make it easier to keep it in place. So can I use silicone with the rubber gasket? Also, the rocker arm sounds like a big job. How can I tell which one to replace.