I've got a 2011, around 130k miles, and I've noticed the idle RPM (warm) will hunt between 500-750 RPM with shakes at 500. Boyfriend suggests the throttle needs to be cleaned, or the PCV valve possibly needs replacement, our friend suggests it might be a misfire.

 

I would agree with your boyfriend and get the throttlebody cleaned. Also check the air filter and PCV valve. Have you had a dead battery or had to jump the car recently? Sometimes the computer loses the information on idle and it will idle oddly. You can go through the relearn process, which is really simple. And you can watch YouTube videos how to do it. Make sure all your maintenance is up-to-date and use a top-tier gasoline.

 

Trying to figure out how to reply to you, but this should work? I got throttle body at the top of my probable causes list, I'll try that and see if it changes. I'll move the air filter to the top of the list though, haven't actually looked at it since I got it only a month or so ago. No dead batteries or jumps. By top-tier, you mean station with good gas or premium gas? I gotta give the whole car an inspection asap though, and comb through the previous records and see what needs to be done.

 

If the air filter is only a month or so old, it should be fine. When I say top-tier fuel, I mean places like Chevron or Shell, major brands are top-tier. Also, Costco sells top-tier fuel. Top-tier fuel has all the additives that you need to help your car run better keep the engine cleaner inside, help increase the combustion inside of the cylinder for better power, etc. it doesn’t have anything to do with whether it’s premium fuel or regular fuel. And don’t make the assumption that if you put premium fuel in, it’s better for your vehicle. Also, when you’re putting the air filter housing back together make sure it’s seated properly and you don’t have any air leaks, and all the assorted wires and vacuum lines are attached to the housing are put on properly and securely

 

Not sure if they replaced the air filter. I looked the other day anyway when I grabbed some fuses but they didn't have it in stock. Yeah definitely, we only use premium in our BMW. I'll have to see what stations are around me because I usually go Harris Teeter or 7/11 since it's on my drive to work. For the housing, will do. Haven't taken a good look at this one yet. Irrelevant to this thread, but any idea how the cold/hot tire pressures differ? Tires were hot but the fronts were around 40 PSI and the rears around 31 PSI.