Do you know what would cause this?

Ok, say im driving doing about 40mph and i come to a stop, i down shift to second and then just drop in neutral and when i do that the rpms drop below 1 and the lights dim like its gonna cut out. The car idles just fine but im just wondering why its doing that and if its a problem.

Might be your alternator going.

battery also, thats what was going on when my battery started going out

Autozone tests both for free.

As everyone else has said, alternator or battery. However, your car is supposed to idle at about 750 rpm, it should not idle above 1000rpm.

I think your right, my alternator might be going now that i think about it.......great
Thanks guys

It's definitely the alternator. Those are the exact same symptoms that my car had while the alternator was dying. Just don't drive your car too much. If you do, you might drain the battery, hence your car won't start.

My TT idles around 1200 or a little higher. If i leave it sit it jumps a bit between about 1500 and a little below 1000. What would be the problem here? if any?

my voltage regulator went out in my altenator. driving it down the road it was past the max voltage. at a stop light it would be at 11. it was bad enough that it blew out my headlights. luckily i had just pulled in my driveway that night they blew out. its most likely ur altenator.

My TT idles around 1200 or a little higher. If i leave it sit it jumps a bit between about 1500 and a little below 1000. What would be the problem here? if any?


Faulty IAC. Irregular idle is caused by vaccuum leaks, spark plugs, and bad o2 sensors. Time to pressure test for boost/vaccuum leaks!