So I went in to the dealer last week for an oil change. Of course they came out and said my cabin air filter was dirty and my break fluid was changing and could use a flush. So I said go ahead. Not a few days and maybe 20 miles after that, I start my car (cold start) and there is this terrible loud whining noise that sounds like a huge hair dryer and the engine was sputtering (mis-fire) and then the engine light started blinking. So I shut it off and opened the hood...the engine cover was gone! They forgot to put it back on at the dealer. So first thing the next morning, I take it in, and of course they say, "Sure the engine cover is gone, but that doesn't have anything to do with your problem." So it ended up being spark plugs and wires. They replaced those (and the engine cover) and the mis-firing stopped but the loud noise on cold start remains. I have read and I think it's the secondary air pump. I find it beyond coincidence that all this happens immediately after I took it in and they forgot to replace the engine cover. The car ran beautifully before all of this with NO problems or funny noises of any kind. What do they do when you take it in and they check it all out? They obviously take things apart to find things that are wrong. They inspected the cabin air filter and removed the engine cover. Would they have messed with the spark plugs/wires or "inspected" the secondary air filter? They must have done something and if they forgot the engine cover, who knows what else they did (or didn't) do.