low idle speed

[ratboy4704]

when i take my foot off the gas of my 2003 325i with manual tranny the idle speed drops to the point that the almost stalls. Dash lights come on the dash, flash and car almost stalls.

Is there a mechanical adjustment I can made to increase the idle?

[Manolito]

No adjustment. Something is wrong.

First

Take some catalyst safe carb cleaner and clean the throttle butterfly and passages in the throttle body. If your throttle disk looks painted (not metal-colored), make sure the cleaner is teflon safe as well.

Look for leaks in air tubes. Check the tube from the mass airflow sensor up to the throttle body. Check the tubes from the throttle body back and forth to the idle air control valve. Note that they generally crack on the bottom first. If you have to remove the IAC valve to check the tubes, clean it with the carb cleaner.

Check the throttle position sensor. I am not familiar with yours, but most TPSs have a little audible click as they come off the idle position. The more reliable check is to use an ohm meter and the service manual to make sure the resistance is correct on all leads throughout the throttle movement.