jeff_c

What would the possible causes of my car stalling when at highway speeds I disengage the clutch and take it out of gear to coast?

I went out with some friends on a little romp up and down 9W New Years Eve (did any body hear us?) and I noticed that if I let the car coast in neutral the idle would get erratic and the car would stall. Regular shifting is not a problem and of course once I put it back in gear it would roar to life. I have no such problems when I'm at a light or at speeds below 30.

While the situation is currently 100% avoidable and not major for now I am afraid that it might be indicating some impeding doom.

Any thoughts or help would be much appreciated.

TIA

Jeff

Happy New Years everyone!

glh

Loose oil cap.... Maybe. Easy to check.

I have seen it affect idle on some models.

jeff_c

I'll check that now.

Thanks.

Jeff

cohare

I have this same problem but have not checked the oil cap. I tried cleaning the MAF and it didnt work. Any other ideas?

rcg412

I had the same problem on a turbo car - was a diverter valve I think. My bet would be it is something vacuum related. Probably something silly.

washington dc porsche

That happened to me once after coasting from high speeds to 0 mph but there was no rough idle.

The only time I've had a rough idle and stalling is when my MAF needed replacing.

nycebo

Do you have a cold air intake installed?

1999Porsche911

And, WHY would someone deliberately coast in neutral from high speeds?

jeff_c

As a matter of fact I do.

Are you suggesting that while at speed there is too much air being introduced to the engine?

btw, the oil cap is on nice and tight

Jeff

jeff_c

In my case, the first time it occurred I just happened to want to coast down a long hill so I pressed in the clutch and took it out of gear. And then after about 5-8 seconds she just stalled.

ZX9RCAM

It happens to me after semi-high speed romps (& high speed) when I go from
6th to neutral & let the clutch out. It has happened twice, but ONLY under
these conditions.

Others have mentioned the same thing as well.

- Cam

cohare

why does it matter if you take it out of gear? Sometimes when coming to a toll at 70 mph, I just take it out of gear and slow down rather than downshifting the whole way.

cohare

Mine happened only twice at first but it is getting worse over time. I would say that it has happened 10 times now.... HELP US!

ZX9RCAM

Does it happen going from 6th gear ONLY, or other gears as well??

s14roller

Not sure what the reason is but it's also happened to me before in other cars I've owned...only when going from WOT to neutal. I wouldnt worry about it to be honest. Sounds like cars just dont like that for whatever reason...probably similiar to if someone just ran hard for 2 miles and just stopped instead of slowing down. Body would respond better if you slow down first...