Had the 1200 coupe with L18 tuned today.

The shop that did it said that the mechanical advance was playing up on the distributor.
At idle, it is reving up past 3000 rpm and staying there then coming down to a normal idle speed.
The mechanic said this is in part due to the mechanical advance on the distributor sticking.
Can anyone collaborate with this story?
I'm going to try and fit another distributor in the next couple of days to see if it fixes the problem.

If it is the timing you should be able to verify the problem by connecting a timing light and watching the timing marks when the engine is revved.
If your mechanic is correct, you will see the timing flash move as he describes.
Better yet get him to demonstrate the fault to you
I'm more inclined to think it may be a binding throttle linkage.
Check all the pivots/cables/return springs etc. and look at the carb mechanism when the problem occurs.
Sticky dist. adv. bits usually only cause rough running because the timing doesn't match the engine speed/conditons.
Make sure all vacuum lines are intact so there are no leaks to the inlet manifold.

_________________
Regards, Graeme
Just trying to help...
http://nissanman.shutterfly.com/
graemes@internode.on.net