Cars jumpy on highway ...

[Powerzen2002]

This is driving me crazy! When I drive street, sometimes when I take off ... the car jumps just a lil, not exactly when I apply gas ... only when going into gear it feels like it is shifting hard (usually as it hits 2nd gear).

On the highway, when I go to gas it ... not full acceleratoin, but enough for good pickup ... it jumps a lil, then when I release the gas there is a small pull back.

I notice the hard shifting changes when I adjust the idle speed.

This all started around the time I noticed that my gas pedal wouold stick a lil when in idle, I would give it gas and the gas pedal would feel stuck. I cleaned the throttle body (the plat and all) very well, but still stuck. SO, you know the piece that is connected to the gas pedal, it holds the wire that pull the butterfly on the throttlebody, well .. I decided to adjust that, putting a lil pull on the butterfly so that it does NOT allow the plate inside to fully 100% close otherwise it gets stuck.

Anway, hopefully all this will make some kind of sense to someone out there.

PLEASE, I need to know if my transmission is going or what to try and do next. OR if I screwed somethign up.. here is more information:

Idle speed in drive: ~700

Idle speed (in neutral):
Warm: ~900 - 1100
Cold: ~1000 - 1200

[bbp]

Check throttle cable. Make sure it is not binding.

Check return spring on throttle body.

That is assuming the jumpyness is engine related and not an alignment or suspension issue, I wasn't quite clear reading your post

[baydevil]

check or replace your spark plugs or wires.. sounds like its not firing everytime its supposed to..

[docrice]

Yeah, i understand what you're saying, i just got a s14 and it is the same way. Sometimes, either starting off or gassing it while cruising it jerks. Usually happens once the car is warmed up, but its getting on my nerves since it didnt do it til 2 days after i bought the car! damn 50/50 warranty probably won't even cover it, but if you guys can help i'd really appreciate it.

[Powerzen2002]

"That is assuming the jumpyness is engine related and not an alignment or suspension issue, I wasn't quite clear reading your post"

What do you mean alignment? You mean wheel alignment? Well that is needed also too, but how would that have anything to do with the jumpyness or jerking?

I just replaced the wires and plugs, already tried that.

I replaced the stock NGK's and wires with Bosch Plat's +2's, and wires with autolites. I see a performance boost, but did not fix my jumpyness/jerking of the car on the highway.

Its really pissing me off! I dont know what else to do.

[mrmephistopheles]

FWIW, stock is always best to keep your motor running right. NGK Rs (or platinums) are best for your KA. Same goes for wires. Stock plugwires tend to make your motor run best. Nissan ignition systems tend to be excellent. It's not too often you see aftermarket ignition on cars like 300zx or Skyline.

[Powerzen2002]

You are right ... the NGK wires and plugs from nissan for the KA engines are basically the only way to go without problems. But, I do notice some improvement over the recommended NGKS with the bosch platinums. As far as wires go, I notice alot of after market like borg n warner's and other crap-o brands tend to make the wire only 7mm instead of the recommended 7.5mm or better wire. (That is where the problem comes in as far as wires,), but autolite makes 7.5mm so I went with them, no problem.

So there you are right, however I dont think that has contributed to this.


Thanks anyway.

[ForceFed97KA]

It sounds like you have an automatic? Is that correct?

If so,

Check fluids.

1. With foot on the brake, if you shift between the gears does it go in smooth, or does it clunk?

2. If while driving, shifting it manualy(d1>d2>d3>d4) does it actually change?

3. When floored does it shift at 33-35mph? Does it give the problem when floored?

4. Do you ever see the OD off light come on, or flicker?

5. Does it ever do it in any other gear? Or is just between 1st and 2nd?

6.Does it still do it when you put the idle back?

[Powerzen2002]

Ok, ....


1. With foot on the brake, if you shift between the gears does it go in smooth, or does it clunk?

- Shifts smooth when gently breaking at high speeds

2. If while driving, shifting it manualy(d1>d2>d3>d4) does it actually change?

- Will try this, but will assume this will work ok.

3. When floored does it shift at 33-35mph? Does it give the problem when floored?

- No, floored its fine.

4. Do you ever see the OD off light come on, or flicker?

- THIS is actually a funny question. ONCE, I seen the light flicker about 5 times. (When I first started the car). But it only happened once.

I DO HOWEVER SEE THE O/D light flicker when I change/re-adjust the idle speed. Then restart the car. Is this normal???

(I adjust the idle speed by, letting the car warm .. rev it a couple of times, then disconnect the throttle sensor - adjust by using the screw ... shut off car, reconnect sensor and test drive. Maybe this is wrong .. I dunno).


5. Does it ever do it in any other gear? Or is just between 1st and 2nd?

- When street driving its gives a jerk when going into 2nd.



* Hopefully my tranny is not going. Thanks.

[sykikchimp]

this is probably a given, but.. have you checked your transmission fluid level?

[ForceFed97KA]

For this question I ment while you were stoped with foot on the brake moving from Park to Reverse to Drive.

1. With foot on the brake, if you shift between the gears does it go in smooth, or does it clunk?

[ForceFed97KA]

Does your MIL light come on?


You may want to check you shift soleniod valves.

but try this first:

1. Start engine and let it warm up to normal operating temp.

2. Then turn car off by turning key to the off position.

Wait at least 5 seconds

3. Turn key to ACC Position.

4. Set the overdrive switch to ON position.

5. Move shifter to Park position.

6. turn key to ON positin but do not start the car.

7. Does the O/D OFF light come on for about 2 secs?

[xhdriver]

might also be a dirty fuel filter

[docrice]

mine is a 5spd and does pretty much the same thing as it sounds like his is doing, so i'm going to check plugs/wires but i think the fuel filter might be our mutual problem...what kind of resistance should i be seeing on stock plug wires if i check them with a multimeter? any ideas? thanks guys

[Powerzen2002]

I didnt check out the O/D light trick yet, havent gotten into the car yet today, will in a few minutes.

However, its NOT the fuel filter, i replace it every 10,000 miles.
I just replaced it less than 3,000 miles ago and did it even
right after I replaced the filter.

Once again, i have new fuel filter, plugs and wires.

Forcedfed .... what will that little O/D light trick you told me to
try and do gonna tell me if it flashes?

[ForceFed97KA]

It starts the self-diagnosis mode, what year is your car?
I am using a service manual of a 97'. I honestly dont know what difference there would be for different years I would assume 95'> would be fairly similar maybe s13 too cant hurt to try.

If the light does not come on it maybe a control unit problem, if it does then we want to watch the sequence of blinks of the O/D OFF LIGHT and note which blink stays on longest.

It should flicker 10 times, we want to note which flicker stays on the longest.

To Start:

1. 1st do the previous steps listed if light comes on continue below.

__________________________________________________ __

1. Turn ingition switch to OFF position

2. Turn ingition switch to ON position (DO NOT START ENGINE)

3. Move shifter to DRIVE position.

4. Turn ignition switch to OFF position.

5. Set overdrive to OFF position.

6. Turn ingition switch to ON position. (DO NOT START ENGINE)
________Now wait for more than 2 seconds_________________

1. Move shifter to the "D2" position.

2. Set Overdrive to ON position.
------------------------------------------------------------------------------------

1. Move shifter to the "D1" position.
2. Set Overdrive to OFF position.

__________________________________________________ __

Press the gas pedal to the floor then release it.

__________________________________________________ __

Now watch the sequence that the O/D off light blinks and record which blink stays on the longest.


Hope this works for you :)

[Powerzen2002]

It didnt work man, didnt it a few times!

Hmmm... anyone else try this on a s13????

Any other ideas!

[ForceFed97KA]

I am sorry to hear that :( . I should have asked what year you had before. In the book it suggests that one possiblity for a sharp
change from 1st to 2nd could be shift solenoid.

This all started from when you changed the idle, if you put it back
the way it was does it still do it? Let me know. If so I would say that that should rule out the trans.

You may want to try to also check all electical connections for corrision. Maybe the IAA valve, I am not sure though I will continue to search.

[Powerzen2002]

Its ok. Is there any other way to check the shift selenoid?

Thanks man appreciate it .. and NO, if i change the idle back I still still am getting the same jump at around 55 MPH / 2000-2300 RPMS

[ForceFed97KA]

To check the shift soleniod, you have to chesk the restance between pin 6 and ground for shift soleniod A and pin 7 and ground for shift soleniod B. But we have no way of know for sure what changes have been made to know for sure that were are checking the right pins Restiance should be zero for both.
another check would be to apply voltage to the shift silenoid and listen operating sound.

Too bad there is no one out there with an S13 service manual willing to help. I'll see if I can find any thing that is for S13 .

[Powerzen2002]

quite honestly, I have no idead what you just said forcedfed :)

haha, it was all gibbirish. I am a complete moron when it
comes to really involved stuff like this. Where exactly are the
pins (shift selenoid???)

I just checked my chiltons book and I could find nothing
on a shift selenoid.

Grrrr. Thanks.