I own a 2004 crossfrie with 50k miles. Sometimes when I stop at a red light or stop sign the car will idle to 300-500rpm, and it will shake the car. Other then this is has no problems no warning lights and no trouble code when I hook my obd II reader to which is expected because these no lights. Anyone else have this issue or know what I should do...besides take it to a dealer which will be glad to take my money.

 

Sounds like the IAC (idle air controller). This usually goes out at higher miles on most cars, but this is not like most cars.

Just vent and let it out in the forum, then go take it in or replace the IAC yourself.

I hate MB.

But try looking up "Throttle Reset" first.

 

how bad of a shake are you talking about?

My brand new '07 XF does this with 4000 miles on it.

When idling at lights, occasionally there's a slight "rumble" and the car shakes a little. It's absolutely noiseless but the idle does dip around 4-500 rpm for a split second.

 

Its a fairly bad rumble...also theres no throttle response until you let off the brake and let it roll forward...its weird

 

Seems a lot of this is going around lately.
Sounds like your MAF may be itching to fail or it's dirty. Try scoring a can of MAF cleaner, pop off your intake & squeeze off a few shots at the MAF assy. It's worth a shot!

 

Sorry chevyboyac, but you are experiencing a common problem to German cars.

Very, very difficult to diagnose. Over time it may get worse and the CEL may come on. Problem may be related to MAF sensor, may be related to O2 sensors, or some piece of the emissions equipment.

A good thing to have may be something like OBDKEY, which allows you to read all the sensors real time and display on a computer. Then you will be able to see if any sensor is stuck, giving you bad values. The price ($150ish) is worth it if you think about all the headache you are saving.

 

could be a leak on your vacume line going to the factory elbow leading to the throtle body. people experienced these same symptoms on the first batch of needwings intakes when the vacume port was located too far from the throtle body and lost vacume.