Two systems are used: centrifugal and vacuum.How does the ignition timing advance work,
With the engine idling at normal operating temperature and the vacuum pipe removed the timing marks on the pulley and the cover should appear stationary and should be aligned. Inside the distributor is the centrifugal advance which, as the engine speed increases, causes the marks to separate. When the vacuum pipe is re-connected the marks will move further apart as the engine speed increases because of the vacuum advance. To adjust the timing loosen the clamp at the bottom of the distributor and turn the distributor until the marks are aligned.
If you can not see a difference in the timing as you increase the engine revs then it is possible that the centrifugal advance is not working as it should.
I don't think it is possible to reset the timing advance as such. The car is continually adjusting that as you drive. They probably advanced the ignition.he says it was specifically the timing advance they reset
The throttle switch is actually a double micro-switch. One switch is activated at idle and the other during 'full load' conditions. So it should click as soon as you put pressure on it but should also click when you get to 'full load' conditions.
One thing I did not ask about is the condition of the air filter element. Make sure it is clean.
Also check the ground wires on the intake manifold. There are quite a few so make sure they are all correctly connected. Check the connectors for the air mass meter, air control valve, knock sensor and coolant temperature sensor. They should be all correctly connected and not loose. Check that the knock sensor and coolant temperature sensor wires have not been interchanged by a previous owner. The knock sensor wires are green and the coolant temp sensor yellow.
Most multi-meters will measure resistance. I alway use digital for accuracy. I have not compiled the resistances yet but should be able to post them tomorrow if you still need them.
Bill.