Whats wrong with my ride?

i have a 1985 Nissan 300ZX, this was a good running car, it sat up for about four years. after getting it running again, it ran good for about 300 miles.then it went cu pook! and stoped running and would’n start. after putting on a new fuel pump,fuel regulator,strainer and a tune up it starts,but will not idle. i have to keep my foot on the gas just a little it runs fine. but each time i put it in gear it goes dead. it will start back up ok,it only runs if i keep the gas peddle down a little. but dies each time i put it in gear again. can you PLEASE help ME?? THANK YOU!!

The first suspect might be the Idle Air Control Valve. You might try removing it and thoroughly cleaning it with aerosol carb cleaner.
Gummed up and sticking IACs are a fairly common problem on just about any make of car and considering this one sat for 4 years that would be what I would look at first. Hope that helps.

I think that a 1985 300ZX is carbureted, not fuel injected. Google seems to support that (47000 hits for ‘1985 300ZX carburetor’). But there is so much garbage on the internet nowadays, it is hard to be sure.

Eventually, you should probably give the carburetor a healthy shot of carb cleaner, and adjust the idle screw on the carburetor.

But first, you need to find out why it is stalling when you put it in gear. Could be either fuel delivery or electronics. Since you’ve replaced much of the fuel delivery system, maybe check the electronics. For starters, if the plugs are easy to get to as they are on many 1970-1980 vintage cars, try pulling the spark plug wires one by one. If there some cylinders where the car runs the same with or without the plug hooked up, suspect a bad sparkplug wire, loose connection at the distributor head, bad distributor head or rotor. If spark seems OK, borrow or buy (they are cheap) a timing light and check the timing. Maybe it will turn out that all you have to do is loosen a bolt and twist the distributor a bit.

Beyond that, look for a mechanic with a lot of grey hair who may remember how to diagnose and set up a non-fuel injected engine.

Allowing the vehicle to sit for that period of time may have resulted in gum/varnish deposits to form in the idle circuit of the carb, thereby not allowing fuel into the engine during idle conditions. You might try adding a can of SeaFoam to a full tank of gas to remove these deposits. Also, locate the idle mixture screws and while counting the number of turns, turn the idle mixture screws all the way in until they’re seated, then turn them back out the same number of turns. This sometimes breaks up the deposits in the idle circuit enough to get fuel to start passing through. And the SeaFoam will help to clean out any deposits that are left.


All I can add here is that you really need to check and probably replace every vacuum line around the engine. I’ll bet there are a lot of them. There should be a diagram on a sticker under the hood. Cracked rubber lines leak vacuum and the entire pollution control system runs on vacuum. Also, if it is an automatic transmission there may even be vacuum lines associated with the tranny, and that could explain why it stalls in gear. The hoses are cheap and you can replace them, one at a time.

The car should have fuel injection.
The last Z cars to use carburetors were the 70s era 240 and 260 Z models which were fitted with 2 side-draft SU style carbs.

When the 280 ZX was introduced around '76 they were fitted with FI from then on.