16v GTi - stalling/dropping revs

September 01, 2022, 06:56:04 PM

Me again. I’ve had an intermittent problem that won’t go away. The car is generally running really well now with only one problem left (for now). When approaching a stop and letting off the accelerator, the revs will drop almost to nothing and the engine nearly stalls. Sometimes it does stall.

ie approach a junction, brake, clutch, revs fall, engine stalls.

Previously it’s been diagnosed as a vacuum hose loose/disconnected. But now it’s still happening and seems to be sometimes intermittent.

Is this likely to be vacuum hose related? If so is there any way I can test/check the pipes for leaks?!

Re: 16v GTi - stalling/dropping revs

Reply #1 – September 01, 2022, 09:30:03 PM

My 8v k jet did this shortly after having the entire fuel system reconditioned so I knew it wasn’t that and it turned out to be a vac leak so I’m still edging towards that.

I don’t know if the 16v has the same but there’s a rubber Y piece of hose around the air valve and servo area. For me It was split in the crotch of the Y, I know it could be anything but I thought I’d call out this particular part as it’s not something you’d ever see.

To test for vac leaks have the engine idle and use a catalyst, brake or carb cleaner works well but I think you’ll get a similar results with simple wd40.

So spray what you have around the engine bay following the route of pipes and hoses.

If the idle speed changes it will be as a result of the catalyst being sucked in and used for fuel.