Car Shaking/Check Engine Light/High RPM on idle
 

So this happened in a short time period. Over this past weekend I was driving my car and at stop lights I noticed the car was shaking, it went away when I accelerated. Then when I woke up this morning my check engine light came on and the shaking of the engine was worse. The engine seems to be louder than usual. I drove immediately to auto zone and got the following codes:

P0300 - random misfire
P0301 - Cylinder 1 misfire
P0302 - Cylinder 2 misfire
P0303 - Cylinder 3 misfire
P0304 - Cylinder 4 misfire
P0507 - Idle Air Control System RPM higher than expected
P0171 - System too lean (Bank 1)

When the car is in motion everything seems fine except for the check engine light being on.

Any ideas?

I changed the ignition coils and spark plugs when the recall happened about 2 or 3 years ago. I also need an oil change and I will be doing that any day now.

Also I changed the timing belt when I had 90,000 miles, I now have 156,000 miles.

That sounds more like a vaccuum or intake leak.

Hmm
 

Sounds like a PCV issue. I had the exact same problems, misfire at idle along with all those misfire codes. Have a reach under and check all the pcv lines and hoses. Turns out the one connecting to the oil filter was disintegrating as when we pulled it off it literally crumbled.

Sounds like a some sort of VAC leak, I agree with lyleswk.

Check your suction jet pump...(do a search for the item, because I don't have any photos)

Gentlemen,

Thank you for the replies. It was a vacuum leak. I had a mechanic replace the black plastic valve, cost me $180. I think I got off easy. Car runs like brand new. I hope my audi lasts forever.