i have had my 92 tt since nov. of 04. i must admit very big difference from the "na's". but i was wondering why my idle would dip every time i throw it into nuetral while i am slowing down. i also noticed that it does the same thing when i rev the car in place. i would rev it to about 4000 rpms and then on its way down, it would tap at 0 prm and then go back regular idle. its as if its about to die or something. the check engine light went on as well. i would greatly appreciate anyone's advice or help, thanks.

 

I'm no expert here......... my car does the same thing.......... so does my '02 Tundra, the '01 civic and the '00 mazda. I believe it is the ecu adjusting to the inputs from various components like the tps, maf and the o2 sensors when you lift off of the throttle. I believe it is normal by design. But if the idle drops too low and nearly, or does die, there are some general maintainance issues that should be addressed like........ cleaning t/b's, iacv / aav valves, vaccum leaks and dirty air filters to name a few. Rizz's link page to tt.net has writeups on many of these issues.

 

Mine does the same thing. Downshift instead of coasting. Save your brakes for when you need them.

 

dunno btu the Idle air controll unit might have to do somethign with it. My frineds GST did somethign similar but he woudlk actually stall once in a while.