So i have a 2001 a4tqm and the engine will sometimes die, but generally only when i put the clutch in and idle whilst coming to a stop. usually happens when it is raining. with wipers going, fan/heat on and lights. it doesn't shudder to a stop, it just seems to simply switch off. I decided to replace the alternator on a whim, thinking that had to be the problem, since it never has a problem starting, but i recently had a subwoofer system in my car, and thought maybe i had messed it up over the past year, though i had a capacitor. I had the old alternator bench tested and was told that i was just fine. When the car dies it generally drops below 12v on the gauge, on average it stays around 13v, never 14v like i thought it should. i did test the alternator on my car with an amp-meter, and ohmmeter, and received reading saying that it was putting out ~14.4 so i don't think that is the problem. replacing the alternator didn't seem to change any of the symptoms. could it be a bad ground? i did check all the brown wires under the coolant expansion tank, freshened up the connection with electronic parts cleaner, wire brush etc. checked around the ecu cleaned out some stuff that accumulated there, it hasn't died on me since then, but there hasn't been any real rainy days, so it could still happen. This didn't bring the voltage back to 14 either. any suggestions? Help?

 

how about the battery? (long shot maybe), or could be a vaccum problem.

 

i agree.. it sounds like more of a idle problem and idling too low.. due to a vacuum leak. possibly you need to clean the throttle body..

 

Sorry, wrong thread, never mind

 

cars doesn't usually die from a vacuum leak. just stumble and run like doo doo.

also if they were to die it doesn't power off like it was hit w/ an EMP.

because you noticed it happens when it rains. to me it sounds like your getting moisture in some major connection. the e box is closed in a way to prevent that, but you never know

 

when letting out off the clutch and idle dropping down if there is a vacuum leak some cars will die, ive seen it a number of times. but this switch off, does that mean like all of the power and lights go off and it turns off or just like you stop getting fire?? or spark??

 

could be the mass air flow is the check engine light on?