Lately the problem has gottena bit worse. When I am at a stop light my idle will drop and the car will feel like its close to dying. It never actually dies, but its a pretty good shake. It used to happen maybe once at a light, but now it will do it maybe 3-4 times. It's pretty noticable too. I notice this does not happen when the A/C is off. What could the cause be?

 

How old is your battery? This could be the cause. The AC is a high drain, an if the battery or charging system is weak, it could pull it down during idle.

 

same ordeal here!!!

 

I did just install 2 amplifiers... I know I have not changed the battery since I took ownership of the car. Perhaps it is the original from 2006? Any way to tell?

 

I just took my car in Thursday for this problem.

They gave the car back to me Friday stating that they did get a fuel mixture trouble code? and that they know there is a problem, but there is not enough sufficient evidence to indicate what the cause is.

I even supplied them with videos of the idle. They said the problem has to get worse for us to fix it...great

In my case it does exactly what you're saying, and it even almost stalled when coming to a stop. I was going about 50mph, hard braking to the light, rpm's dropped well under 500, car jerked back and forth like a stall, then caught it and rpms rose back up.

I don't know how much more evidence they want. Maybe they want me to tow my car there with a f'd up transmission for them to tell me "ohhh, the transmission is broke, thats why your car is having problems" lol. Thank you mr. obvious.

Please let us know if you find anything out.

I'll post videos of the idle to reference the symptoms and help us out.

 

Same problem here...They told me that there was too much ethanol in the gas...I changed the gas only to discover that that wasn't the problem. It's whenever the "snowflake" button is on the car shakes at idle. Turn the "snowflake" off car is fine. I"m gonna take it to another dealership and hopefully they can solve the problem. I have an 08 BMW 550i....

 

I don't know how to tell, but the issue, does sound like it could be charging/battery related. The addition of the two amps, on top of the load required for the A/C is alot. Did you notice if it became more consistent after the amps were added?

 

Yes, the problem got worse after I installed the 2 amps. I don't see how the battery would be a problem when the car is running though... It could be a coincidence and the problem was going to get worse anyhow. I have not changed sources of gas since buying the car so I don't think gas is the problem. I even tried running only Chevron gas for a couple fillups. That didn't help.

The guy above posted about the "snowflake" button. That is what makes the AC cold. It could be that when that button is off the AC compressor doesn't run. I will try that and see if it helps. I'l report back.

 

How many miles do you have on your car? It is possible that A\C compressor is going bad (or the A\C compressor clutch).

 

When it is happening, open the hood and see if the fan is on and is blowing hard. It could be because the condenser fan is not working and causing the ac system pressure to be extremely high at idle.