Hi all,
Randomly on the last drive, when engine was warm, when I dip the clutch the revs drop so low it stalls.
Ended up having to re-start every time pulling up to traffic lights. Also tested just dipping whilst driving along and stalls as well (but obviously can re-start lifting clutch agin).
Any ideas? Completely random and wasn’t doing it before….
Unmodified 180bhp 25k VHPD.
Thanks in advance.
Blocked IACV.
Thank you.
For the mechanically inept, what does this require?
Hopefully this helps 
How to Clean a Throttle Body and Idle Air Control ( IAC ) Valve - Quick and Easy - YouTube
Thanks very much
Used to happen to me then, suddenly, it didn’t. Hope you cure it.
As in you didn’t do anything to fix?
Make sure there are no splits in the vacuum hoses or the T-piece connectors.
If the above suggestions don’t work, it might be worth setting up the idle speed so that the IACV is almost closed at warm idle. Just wait until it’s warm, keep adjusting the idle screw until the speed increases (nothing will happen initially, as the IACV will close as the throttles open), and then back it off slightly once the revs rise.
Well, nothing specific was tried , so could not be sure what, if anything, cured it. Maybe just regular use
Did you get it fixed? Interestingly enougH, tonight I discovered that if you reset the idle learning on the ECU, it shuts the IACV fully (33% DC) then varies the idle speed between 1500 and 750 rpm, so must technically be capable of running without one!
Apologies for slow reply but yes.
Simply screwed in the small adjuster on the throttle cable a half turn. It has solved the problem but will have a technician check it over when I next go for a service.
Interestingly (or not) another niggle surfaced when at cadwell. The car developed a phantom 5k-5.5k rev limit then was fine driving home…. Theory is a crank sensor issue but again something to check out.
Good to hear! The only thing to watch out that by increasing the idle speed that you’re not masking another issue. Easy to check though with an OBD, check that the idle speed matches the target speed, and that it can get down to 1250 rpm when cold. If you see the ‘idle DC’ start to get up above 45% then that could point to the IACV sticking.
Thanks for the advice. The idle adjustment only being used temporary fix until goes for service shortly.