Last try on this issue

[Chickenman]

Some good suggestion have already been made above. You're going to have to do your best Sherlock Holmes impression and hunt this down systematically.

Regarding your intermittent running problem. I suspect a poor electrical connection could be your issue. This often happens on Vintage cars and occurs randonly when the car hits some bumps or pot holes in the road.

One way of checking for this is to run the car over a rough railway crossing a few times. Make DARNED sure that you have enough speed to clear the crossing if the engine conks out!!!

Start checking ALL of your grounds and pull apart all of the connections in the engine bay and clean them with DeOxit or a similar purpose made electrical cleaner ( Weicon is amazing ). Look for frayed and loose connections. Pay particular attention to the ignition circuit. Don't forget the relays hidden under the passenger side relay cover. I'd carry a test light and a Volt Ohm Meter with you at all times to check for voltages and continuity when the thing eventually conks out.

Might be a good idea to replace the ignition switch with a new one just to be on the safe side. These get a lot of use and are often over looked.

Edited October 30, 2014 by Chickenman

[Chickenman]

I noticed your car is a 1976, same as mine. Do you have the Federal distributor with the two sets of coil pickups or the California model with only 1.

Sometimes the pickup coil will go bad and will work intermittently. If you have a 2 pickups in the Dizzy and you lose ignition spark you can do a quick switch of the coil pickups to test. The " advanced " pickup ( Secondary ) is only used when the engine is cold. The " retarded " pickup ( Primary ) is used when the engine is warmed up. There is a 3 way connector just above the Ignition coil.

If you suspect that the Primary pickup coil has failed, you can switch the leads around at the 3 way connector and run the car on the Secondary pickup.

Really the best thing you could do with a 1976 is to replace the distributor with a later model ( 79 - 81 280ZX ) that uses the E12-80 module.

BTW, Rock Auto has a great deal on re-manufactured 1979 280ZX Distributors. A-1 Cardone ( a good brand ) for only $90.79 + $15 core charge. Great deal!! Rock Auto Part #31619:

Product Detail

Edited October 30, 2014 by Chickenman

[siteunseen]

Really the best thing you could do with a 1976 is to replace the distributor with a later model ( 79 - 81 280ZX ) that uses the E12-80 module.

BTW, Rock Auto has a great deal on re-manufactured 1979 280ZX Distributors. A-1 Cardone ( a good brand ) for only $90.79 + $15 core charge. Great deal!! Rock Auto Part #31619:

Product Detail

I bought that same distributor and a Crane PS20 Fireball coil from amazon. The distributor was a little more than $100 but no core charge and free shipping. The coil was around $40. Great set up on my 240Z, highly recommended.