Idle Problem.. Help would be appreciated!

[bbiksey007]

Before I get started I just want to say that I've already done a great deal of searching and nothing I've found is quite like my problem.

So heres the deal: I crank my car and no problem. It idles at 1000Rpm in park. I shift into Drive (Yeah its automatic, sucks I know ) and the 40 acts kind fenicky or splutters for about 5 secs or so then once it gets past about 1300Rpm she comes alive and drives fine. Now heres the real problem: When I pull up to a Redlight the car idles at 700Rpm like it should at first but after a couple of seconds the idle bounces slightly up and down and often my car will jerk back and forth slightly like a fat guy is trying to push and pull my car or something, now shes never died at a redlight but gets close sometimes. Lately I've just been shifting into Neutral at redlights because it will idle firmly at 1000Rpm just like it does in park with No signs of issues.

Does anyone have any ideas as to what it could be, has this happened to anyone and knows how to solve my issue?
I'm thinking vacuum leak, injectors, fuel filter, or fuel pump. I just need to narrow it down because I work ALOT and dont have much free time to trouble shoot. Thanks guys

[nissangirl74]

My best guess would be a transmission issue, considering it only happens under load. I'm sure there will be lots of people in here a lot smarter than me who will give you more knowledgeable input but in the meantime, I'd start reading the FSM and begin the trouble-shooting process. Good luck!

[Razi]

+1 On checking the factory service manual.

Click here:
http://www.nicoclub.com/FSM/240sx/91-94/
And download EC.pdf and jump to Page 33 and check out all the issues that have to do with idling, it should have a lot of diagnostic procedures.

But first, you should check for error codes at the ECU.
Helpful tutorial:
http://www.ka24development.com/ecu_codes.html

[bbiksey007]

Thanks for your imput guys

UPDATE: I touble shooted alittle bit today. I checked the ohms for each of my injectors and all of them read 11.x so I know the coils arent bad in them. I unplugged 1 injector at a time and each one made my engine run bad and set back into idle once plugged back in so I know my injectors are good and there isnt any miss firing.. I fiddled with the idle adjustment screw and no matter if its tightened all the way or lossened all the way there was No change in idle. Now I unplugged my MAF sensor and the idle went to about 800 and when I took it for a test drive my car wasnt hessitant at all when 1st driving off once I got to about 3000rpm my car wouldnt accelerate anymore and would make this vroom vroom vroom sound when putting on the gas. However, when I slowed to a stop my car didnt jerk back and forth NOT ONE bit and the idle stayed stable and didnt bounce. Does this sound like a bad MAF sensor? Or do you think it may just need to be cleaned and will fix my problem?
I Appreciate any more info, and I feel like I'm getting close to solving this with you guys help

[costa_rican13]

well i would suspect your iacv, because your screw didnt make a change whether screwed in or out all the way.

[420sxWETDREAMS]

well i would suspect your iacv, because your screw didnt make a change whether screwed in or out all the way.

I have the same issue except I have a stick shift. I adjusted my iacv and noticed a different because it was idling under 1000 and was shutting off when cold and would go up and down between 1000 and 700. after I adjusted the iacv wire until it was idling around 1000 It was better, hovering over 1000 by a little bit, but it is still going up and down as well.

[dope240sx]

Am having almost the same problem after my car warms up the rpm moves from 1000 to 700 slowly up and down in neutral
Its a 1990 240sx ka24e
Did you guys fix ur problems?