Today, when I parked my car, I noticed that the RPM needle kept moving up and down ranging from 500-800ish and felt the car shake. I popped my hood and can see my engine shake/rattle everytime. What may be the problem?

 

Any number of things.. Fuel filter, plugs, EGR valve, dirty injectors, or dirty intake manifold... Is the check engine light on?

 

First thing I would try, is Sea Foam. CLICK ME!

 

He beat me to it... I had thought it and was going to post it, but whatever

If no check engine light this should help.

 

you could also try checking plugs, wires, and dizzy

 

If the rpms are surging It could be a dirty ICV (idle control valve) I had that problem o nmy bimmer, I took it oof and cleaned it and it fixed the problem

 

Also check your vacuum hoses.

 

I want to ask for a clarification...

When pouring the Seafoam "into the crankcase", are you refering to removing the spark plugs and pouring an amount directly into each cylinder, or down to blend with the oil?

 

Use the vacuum hose off the power brake assy. You don't want to suck the seafoam all at once, just let sip it slowly while working the accelerator linkage.

 

cleaning the screen in your idle control valve can possibly help. instead of a low idle i was getting a high idle. i was also getting a cel. but after cleaning the screen on the icv i haven't any problems since then. also you might want to see if your a/f mixture might be lean or rich.