I recently got a 75 280z which was sitting for several years. When I got the car, it wouldn't start and had no brakes. After a new fuel pump, fuel filter, plugs, wires, cap, rotor, starter, battery, and some intake and oil cleaning it runs. problem now is if I turn it on and let it sit for a while (roughly 10 minutes) it will die out. I rewired the maf, and took off the cover and made sure all of the connections were ok. Seemed to be ok for a while, but now its doing the same thing. And whats kind of odd is when its about to die out, if I hit the gas I can hear the fuel pump relay under the dash click.

As far as the brakes go, I put on a new master cyl. brake hoses, pads, rotors, shoes, drums, spring kits, and wheel cyl.'s. I cannot for the life of me get a brake pedal. It just goes all the way down. It does brake, just very poorly. I thought maybe the push-rod was not adjusted so I tweaked it a little.... still nothing.

Any suggestions on either of these problems would be greatly appreciated!

Jiman- as far as your brake issue goes, IF you are POSITIVE everything has been bled properly, caliper bleeders are in the right orientation(at the top) check and make sure the reaction disc is on the brake master rod in the booster. There is a small rubber disc that is on the back side of that rod inside the booster. If it has fallen off you will play hell trying to get your brakes right. Don't ask me how I know. Do some searching for "reaction disc" and see if the symptoms you are experiencing relate. BTW, Welcome to the site. You will find lots of experience here. I know I have.

Interesting, that seems to be exactly what I am experiencing. I will dig into that this weekend. Thanks for the advice!

1975 has the fuel pump contact switch in the AFM (Air Flow Meter, not maf). It might be that after the car warms up and the idle drops down (because your Auxiliary Air Regulator is working, a good thing) the contacts are opening, killing power to the pump. My 1976 used to do that and I also could hear the relay clicking. When it got close to dying, you could hear the relay clicking on and off, in time to give it some gas. My problem was a poorly adjusted rebuilt AFM, but if your car has been sitting you probably have other issues.

I would look for vacuum leaks in the intake system, which would be letting air around the AFM. The system is designed to have all air come through the AFM. Short term, you could just turn the idle up high enough to keep the AFM flapper off the contact, while you look for leaks and tune it up.

The Engine Fuel (EF) section of the FSM is well worth reading - http://www.xenons30.com/reference.html

Air in the system or rear drums are waaaay out of adjustment. Power bleed the system. Tighten the star wheel on each wheel cylinder/drum until the wheel stops with one revolution when you spin it by hand.

I bled the brakes about 3 different times, and the drums are well adjusted.

About vacuum leaks, I did a smoke test on the engine, and it held pretty well but there is a slight leak at the throttle body where the tps mounts up and on the opposite side of the body (so the rod that mounts to the butterfly valve is leaking on both sides) but the leak is very small.

Also when you turn it on right after it stalls, it will do a sweeping idle between 200 and 1000 rpm a couple times, then die.(Unless you hit the gas, which is where you can hear the fuel pump relay click)

What Zed Head said! When you step on the accelerator, the throttle lets more air in, the vane on the AFM swings open, the fuel pump cutoff switch closes, the FP relay clicks, the pump runs, and the system repressurizes.

When you replaced the master cylinder, did you bench bleed it? If you didn't, with someone holding the pedal down, crack the bleeder screws on the side of the master just under the bowls. If you get air, do it a couple of times until no more air, then rebleed the system.