Any cage mechanics on here?

[Hawkeye]

Well there's ya problem right there

Expected this kind of response. But from more than just one.

[Phreak]

Your idle is too high. Does it 'clunk' when you put it into gear before dying? If so, you probably need a new gearbox. Try doing a transmission fluid flush and change first, might help... If it were me, I'd swap in a manual box and clutch set-up. Gonna cost you a little bit more, but easier (and probably cheaper) in the long run. Auto 'boxes are a prick of a thing to fix. I had one that went real bad a few years ago that ended up setting me back about $2000 to sort out. But yeah, check for vacuum leaks and plug connections to the gearbox, might just be a dodgy terminal. Can't really say much else without looking at it in person.

*By the way I'm a qualified auto-sparky. Going from past experience (my dad used to have an RVR the same.)

Good luck!

[BoristheBiter]

Try doing a tranny fluid flush and change first,

Good luck!

I think you can get a cheap one up K road...... or so I've heard.

[Rhys]

Check the timing and drop the idle back, it should be idling at about 800 rpm. At 1200 rpm the transmission is trying to drive the car so hence the clunk as it goes into gear

[pete376403]

. Auto 'boxes are a prick of a thing to fix. I had one that went real bad a few years ago that ended up setting me back about $2000 to sort out.

Auto boxes, like most things, are easy to fix if you have the knowlege and tools.

The gearbox issue is not the problem here - it's a result of the high idle. The idle speed is high because that is what it takes to keep the motor running.
Assuming this particular problem did not exist before the engine was worked on - what has been done to the engine? Cylinder head removed, which means manifolds, fuel system various hoses and pipes have been disturbed. I'd be looking for (as has already been suggested) a vacuum leak, probably as a result of either a hose/pipe left off or a misplaced gasket / o-ring. It has to be on the inlet side, so search around the inlet manifold, throttle body.