A hand held vaccum guage can tell if there is possible a gasket leak. I'd
plug mine in and rev the engine at idle. I suppose a dash-mounted vacuum
guage might show something when the problem actually occurs. There's a
guide to diagnosing engine problems with a vacuum guage on my website (see
below) under "Cars".

I have a Chilton import car manual for 1983-90 but it doesn't show if the
626 has transistorized points in the distributor. When that starts to go
you can get intermittent timing problems but I can't imagine how it can
cause such delayed ignition after the ignition is turned off. Some auto
parts stores will test the ignition module for free. I've had one off an
'89 Fesitva (Ford/Mazda) tested. The printout test for low and high speed
conditions so they differ somehow.

As for possible emisson control problems, I don't know what the 82 Mazda
has on it but a Haynes emission control book says the following in the
troubleshooting section:

Hesitation or stumble on acceleration:
- defective acclerator pump in carburettor
- defective throttle position sensor or circuit
- defective air temperature sensor or circuit
- defective MAP (mass air pressure?) sensor or circuit
- ignition timing
- trottle bore or plate

Backfiring:
- vacuum leak in PCV or canister purge line
- defective air injection valve
- ignition timing

Engine diesels (runs on) when shut off or dies too fast:
(preignition?)
- vacuum leak
- EGR valuve stuck closed causing overheating
- heat control valve stuck closed
- idle speed too high
- excessive engine operating temperature

Hope that helps.


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