When my Beetle is warmed up, she gets increasingly rough idling in gear, and reallywants to stall. Usually happens after 15-20 mins of driving. Eden adjusted the idle up a bit for me on the weekend, and that has helped (much smoother driving all round) but she still shakes and wants to stall when I'm perched at lights.
She is starting first go, no probs there.... there's no backfiring or anything either.

Any ideas as to what it might be?

Was the previous problem of stopping completely sorted out? ie. Has she been behaving herself since then? Was the cause of that (cutting out & not restarting) definitely found?

Could be:
-Blocked fuel filter. Might feel hesitant at higher speeds and gradually get back to normal at idle. Blockage might be invisible "gel" if using some types of lead replacement additives or upper cylinder lubricants containing polymers.
-Sticking fuel pump pushrod. May stop or run very roughly when the crankcase has heated up.
-Idle mixture too lean for smooth running. Some mechanics habitually reset the screw to the theoretical 1-1/2 or 2-1/2 turns out (depending on model). I have been caught before, where I'd found the setting required for smooth idling was 3-1/2 turns out, but the mechanic reset it without me knowing. Once I've got it right now, I put a small dob of grease on the top of screw so I can tell if it's been touched. Good idea to make note of the number of turns out so it can easily be checked/reset.

Thanx ACE!
Will definitely check it out tonight again and see if it's any of those..... :P

All looks fine.
Driving home from work, she was running so rough, and gen light and oil light coming on before I even stopped at lights properly.

D'oh!

Hi,
Try spraying WD40 around various intake joins. If the idle picks up, you've got a leak at that point. Check the control valve hoses as well. Actually you may as well check that the clamps are tightened on the joins as well.
I went through my 71 Semi-auto and wound up replacing the intake manifold rubber boots, manifold and carby feed hose to the control valve.

Hope that helps....

regards
ctefeh

This is an auto stick isnt it. How does it idle in neutral?

Idles ok in neutral.

There are two entries re specific Auto's 'problems' in 2 Manuals that may be relevant:
1. Engine stalls as gear is selected.
2. Engine stalls, will not restart.
These sound familiar problems!
Causes:
1. Hose b/ween control; valve & servo leaking; or Servo diaphragm defective.
2. Hose b/w carb & valve or b/w valve & vacuum tank off or leaking; or Leak in vacuum tank.
The cures are repair/replace hoses or repair/renew vacuum tank. At least you don't have a clutch cable to break suddenly...
These entries are from Bentley's & Gregory's (Scientific Publications) manuals.
I suggested the other things as they are problems that can occur/worsen after the car has been running for a while.

If it idles ok in nuetral and rough in gear then you are down on one cylinder I would say. Check for vacuum leaks first as someone else has said spray WD40 on the rubber parts and joins on the inlet manifolf while the engine is running and in gear. If the idle picks up when you spray on any of the manifold joins or rubber parts then theres your problem. If it doesnt then the problem is further in the motor. Also pull off the plug leads one by one to see if that changes the idle in gear. If you pull off a plug lead and it makes no difference to the idle then thats your problem cylinder. Could be something as easy as a bad spark plug.
Worse case is a pulled head stud, but this usually accompanied buy a dull sort of thudding sound.

I wish I knew more about my Bug.
I've booked her in to the mechanics as I don't trust my observations.
I hope it's not a cylinder prob, as they're brand new ones!