'79 911 Targa SC 121k miles stalling

[Trifecta]

I have owned the car 10+ years and chased a stalling issue for 9 of those years.
Recently had local Porsche classic shop replace the auxiliary air valve ($$$$) and the stalling stopped for 6ish months.
Car now holds a high idle 1900 after warm at stop lights, does not stall.
If you ease the clutch out, idle drops to 1000, holds and stalls.

I have noticed that the injectors are very loose, is that normal?
Could a vacuum leak around the injectors be causing the issue?
To my knowledge the seals have never been replaced, can I test this?

Any feedback greatly appreciated.
JDW

[terryfly]

Injectors are loose on a CIS injection system.. All my CIS reference info is boxed up in my car which at the moment is in transit. But you might want to review the warm up regulator. I think the control on my 75 differs from yours. That said I'd start by confirming the pressure settings. Hopefully your shop did this but if not a tester is pretty straight forward to use and can be (or could be ) had at Harbor fright
You can kit a warm up regulator if need be.
Terry

[YonnieNo.9]

Trifecta, following this closely because I am experiencing a similar issue, though not identical. When I throw the clutch in from high rev (think emergency braking) the car holds briefly at idle then stalls. I am waiting to save some $ before taking it into my local shop for them to diagnose. It would be great to check on a few things at home before I drive it in to the shop.

1978 911 SC

[Tom]

Trifecta, following this closely because I am experiencing a similar issue, though not identical. When I throw the clutch in from high rev (think emergency braking) the car holds briefly at idle then stalls. I am waiting to save some $ before taking it into my local shop for them to diagnose. It would be great to check on a few things at home before I drive it in to the shop.

1978 911 SC

What is your vacuum at idle? Engine vacuum is at its max when you close the throttle at high RPM, so if you have a vacuum leak, it can lean out the mixture and kill the idle. Could be lots of things of course, but vacuum leaks would be high on my list.

[boomvang]

Agree with the vacuum theory, do a smoke test as your first action. Also, how loose are the injectors? It's true that they are not bolted in, but the o-rings that hold them should not be loose.