I have an 1992 nissan 300zx non turbo when I start the car idles fine when driveing ill be constant 50 mph the car jerks around like the idle wants to go down when I let the gas go the idle drops to 800 den to 500 den to 200 den back to 900 up and down like that I cleaned the iac valve it gotten better but did not fix the problem what can this be?

SOURCE: rough idle, dies when trying to give it gas

it'll either be your ignition system (spark plugs, distributor cap, etc) or more likely your fuel system (most likely your fuel pump or your fuel filter)

SOURCE: 1984 nissan 300zx turbo 50th AE

it is adjusted by the idle screw on the aac valve located on the plenum

Marco Avila

• 58 Answers
• Posted on Feb 17, 2009

SOURCE: 1990 300zx non-turbo coupe 5 speed

Old post but I would like to state that white smoke and white vapor are two different thing and blue smoke is sometimes so ligh it looks white but does act like heavy smoke. Evanescence of water vapor looks a lot like smoke but dissipates a lot quicker but in mass quantities can look like smoke (yes..I been dying to use that word ever since I heard of the band Evanescence lol). Transmission fluid can be sucked into the engine via a bad shift modulator both that has no bearing here (just FYI). In either case you would be fouling out spark plugs due to oil or water saturation and causing unburned fuel to be expelled.

SOURCE: timing on a 1991 nissan 300zx

There is no means of setting the timing if you are referring to a conventional timing light. The engine is designed with sensors that sense the angle of the camshafts in relationship to the crankshaft and whether it is on the intake or exhaust stroke on the #1 cylinder. This design is actually a little more complex than that because it has variable valve timing which means that the angle in which the camshafts open and close the valves, change with RPM's This give the engine the best of both worlds. It's like have an engine with cams designed for torque at low RPM and a set of cams designed for HP with a free breathing quick revving engine you would have on a race course. The ECM is constantly changing the timing and injector pulse width based on many sources of input, from, the O2 sensor, air flow, air temp, coolant temp, fuel pressure, RPM's and a host of other inputs.
SO>>>>>>>>>>>> in a manner of speaking, unless you are making reference to setting up the timing chain, everything else is under control by the ECM and related components.

SOURCE: High Idle

I have a 2001 Nissan Altima and mine did the same thing. We replaced the intake gasket. It costs around $5.50, but it requires several different kinds of tools. We spent over $100 in special sockets, etc. But once you replace that gasket, it will idle better.