Why does my rpm needle bounce and my engine shake?

[allshow]

First, when i end up on a stop light my rpm needle bounces up n down and the engine is shaking(like it was stalling). then shortly the engine light turns on, but when i turn on my headlights or the a/c the shaking of both the engine and the needle stops. but when i pop the hood, the engine is still shaking alittle. Can someone help me please!?!?    Also....There's a hisssing sound coming from somewhere around where the transmission fluid dipstick is.?!?!?

[91CRXsiR]

my car is doing almost the same thing...

it could be allot of things
the best thing to do would be to check your ECU to see what code its throwing.

or you could try a few other things

cleaning your battery terminals
cleaning your MAF
checking your timing
check your injectors for a leak
check for vacum leaks as well

[West]

If you look in the Archive and FAQs section you will find your answer.

Its titled...
Major Idle Issues! (http://www.zilvia.net/f/cgi-bin/ikonboard.cgi?act=ST;f=6;t=6639)

[Russki]

I just picked up my S13 today, and when the car is idling, the RPM's move between 1600 and 2000.  I didn't have a chance to check anything yet, but is this something that occurs often?

[camppain]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote (WeST @ Mar. 21 2002,11:43)</td></tr><tr><td id="QUOTE">If you look in the Archive and FAQs section you will find your answer.

Its titled...
Major Idle Issues! (http://www.zilvia.net/f/cgi-bin/ikonboard.cgi?act=ST;f=6;t=6639)</td></tr></table><span id='postcolor'>
yes i agree with mark plus there will be alot added to it this saturday hopefully if mark gets my stuff im emailing him.

i had a quest i was working on for the last 2 days had an idle surge problem when you put it in park
i adjusted the idle &nbsp;ensured the timing was corect first of all. checked the tps voltage. the throttle screw was f/cked with so the throttle plate wouldnt close all the way cause air to get in thought that was it drove the car again still had the same problem.

found the colant temp sensor was disconnected after re checking all the connections and then found anouther connecter not connected. obviously someone was dicking around with it not know what they were doing and forgot a shitload of stuff.

but just go to the archives for now

[gtfour43]

Check for a vacuum leak after the mass air. If there is a leak somewhere it will mess with the reading that the mass air is looking at.This will cause the idle to bounce and the engine to run rough and sometimes die out. That hissing sound should be your vacuum leak. Good Luck!

[allshow]

Thanks people for the tips on what will help me figure out my problem. now my other problem is: where's the MAV at, how do can i check for leaks on my fuel injectors and vacuum? and is it safe for me to check the ecu for codes considering it'll be my first time??

[HKrpS13]

Is this about s13 or s14 or does it go for all car, because I'm having the same problem on s13.
I think mines pretty bad because every time the gear goes in nutural, the engines goes off because of low rpm, so everytime I change gears I gotta do it quick. But sometimes the car just runs smooth. Well I'm going to go try what it says.
Q. Does this problem cause the check engine light to go on?

[XxDriverxX]

Hmm.. mine was doing that, I turned off the O/D and it's gone, lol.

[HKrpS13]

I git mine fixed!
Reason why it was doing this is because i had water inside the spark plugs. I guess it went inside when I was washing the engine room. All i did was stick a paper towel inside each one. Try it and see how it goes.

[HKrpS13]

did any one try it and got it fixed?

[Russki]

I changed all plugs/wires and it still idles at about 1800 rpm in neutral. &nbsp;I found the idle adjust screw ( i think that's what it is, it's on the left side of the intake in a hole) and tried adjusting it, and I screwed it in all the way and the rpm went down from 1800 to only about 1650.

The all knowing S13GRL, is there anything else that can be adjusted to fix this? &nbsp;Could the computer be at fault? Please help. At every stop light it sounds like i'm revving the engine and I think it's killing my MPG.

[geeaj]

</span><table border="0" align="center" width="95%" cellpadding="3" cellspacing="1"><tr><td>Quote </td></tr><tr><td id="QUOTE">Thanks people for the tips on what will help me figure out my problem. now my other problem is: where's the MAV at, how do can i check for leaks on my fuel injectors and vacuum? and is it safe for me to check the ecu for codes considering it'll be my first time??</td></tr></table><span id='postcolor'>

MAF, not MAV is located at the end of your intake piping, it mounted to your stock airbox or where your aftermarket filter mounts too if you've changed it. The body is made of aluminum and it has a sensor plugged to it.

As far as vacuum leaks, the easy way is to get a stethoscope or a piece of rubber tubing and listen around rubber hoses. You will hear a distinct "hiss" if it is leaking. Othewise, you need a vacuum gauge which measures in inches of mercury.

Fuel injectors, look for leaks and gasoline "crust" around the intake plenum and the fuel rail. Also, check for any gasoline smells around the area. Usually if they are leaking, your performance and gas mileage will go down hill. If your rings are worn, you may also end up with gasoline in your oil.

To check ECU codes, goto http://www.240sx.org and read the FAQ.

Good luck.