RPM drops fast when declutching sometimes stall

Reply Subscribe

Thread Tools

Search this Thread

Jun 18, 2018 | 03:28 PM

Moonspin

Thread Starter

Junior Member

Joined: Nov 2017

Posts: 37

Likes: 0

From: Ontario

RPM drops fast when declutching sometimes stall

Car is s5 t2
Car starts and idles fine (little bit white smoke on cold start, only last for ~6 sec)
When I declutch, RPM drops quickly (drop to <500 then come back to idle speed). Sometimes it seems like it drops too hard (especially declutch from 3rd, 4th gear) and the engine just stops.... kinda dangerous on the road..
I did some research, one possible reason is a dirty throttle body and clogged idle air control valve.
Any ideas on other possible reason?

When I remove the intercooler and throttle body to clean it, is there anything I should pay attention to? Do I need to adjust TPS after I put them back?

Thanks in advance guys.

Aug 8, 2018 | 07:18 AM

tomatoto

Eric Seven

Joined: Apr 2018

Posts: 276

Likes: 32

From: France

I've no idea, sorry. But I just wanted to know if you managed to fix it and how ?

Aug 9, 2018 | 12:42 PM

NCross

I have a rotary addiction

iTrader: (18)

Joined: Jun 2006

Posts: 4,815

Likes: 24

From: Columbia, Tennessee

If your idle, TPS, and timing are all set properly I would suspect a failed BAC. Pretty common. If you have working AC, does the idle dip down when you turn the AC compressor on? What about when you turn the headlights on and off?

Last edited by NCross; Aug 9, 2018 at 12:45 PM.