# Car studdering/hesitating need HELP!

**URL:** <https://forums.speedlife.net/t/car-studdering-hesitating-need-help/115102>\
**Category:** SON240sx Automotive\
**Created:** [April 30, 2008, 12:02pm UTC](https://forums.speedlife.net/t/car-studdering-hesitating-need-help/115102 "2008-04-30T12:02:30Z")\
**Posts on this page:** 5\
**Page:** 1

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**Author:** ![Champz](https://avatars.discourse-cdn.com/v4/letter/c/ecc23a/32.png) [@Champz](https://forums.speedlife.net/u/Champz)\
**Post date:** [April 30, 2008, 12:02pm UTC](https://forums.speedlife.net/t/car-studdering-hesitating-need-help/115102/1 "2008-04-30T12:02:30Z")

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Hey guys, need some help with some problems.

The car is nissan 240sx 91 w/ a ka24de. ill try to explain everything as much as possible, soo…

I just recently change out my whole fuel pump assembly cause it was rusted out. so i replaced everything and put it bak, everything was fine until the car starts studdering when in neutral, it will drop down to 500 rpm and starting studdering, until i have to hold the gas. sometimes when i make a complete stop, the car would just turn off. Even in 1st and 2nd a hesitation from the engine

I thought it could be a fuel filter, so i replaced it with 300zx one, still the same problem occurs.

If anybody can lead me to the right direction, it would be much appreciated since this car is my only car

thanks in advance  
champz

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**Author:** ![DJPyro](https://avatars.discourse-cdn.com/v4/letter/d/278dde/32.png) [@DJPyro](https://forums.speedlife.net/u/DJPyro)\
**Post date:** [April 30, 2008, 1:05pm UTC](https://forums.speedlife.net/t/car-studdering-hesitating-need-help/115102/2 "2008-04-30T13:05:29Z")

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Make sure the wiring to the fuel pump is good, make sure there’s no pinches or kinks in the lines… Check some stuff outside the fuel system, air filter, MAF, things like that… Could be something else went bad at the same time.

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**Author:** ![knockturnal](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/knockturnal/32/5687_2.png) [@knockturnal](https://forums.speedlife.net/u/knockturnal)\
**Post date:** [April 30, 2008, 3:58pm UTC](https://forums.speedlife.net/t/car-studdering-hesitating-need-help/115102/3 "2008-04-30T15:58:46Z")

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There are tiny black Vacuum lines that run to the Intake there can be a Small hole in on or more of them check all of them if you have the time take them out one at a time and inspect them , make sure you Mark which ones you inspected , it can be confusing

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**Author:** ![Champz](https://avatars.discourse-cdn.com/v4/letter/c/ecc23a/32.png) [@Champz](https://forums.speedlife.net/u/Champz)\
**Post date:** [May 2, 2008, 12:48pm UTC](https://forums.speedlife.net/t/car-studdering-hesitating-need-help/115102/4 "2008-05-02T12:48:52Z")

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Thanks guys,

ya found the problem, it was one of the vacuum lines on the intake it was loose, causing me to idle badly, so got that fix and idling is good but the only problem now is when i shift in 2nd and when i accelerate fast the car starts to hesitate between 2-3rpm and the car rocks back forth, but if i accelerate slowly no problems, any idea what may be the cause of that?

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**Author:** ![knockturnal](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/knockturnal/32/5687_2.png) [@knockturnal](https://forums.speedlife.net/u/knockturnal)\
**Post date:** [May 3, 2008, 5:11pm UTC](https://forums.speedlife.net/t/car-studdering-hesitating-need-help/115102/5 "2008-05-03T17:11:00Z")

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Throttle Position Sensor maybe?

I dont know where it is , on my FC i know and its a big ugly unit that i had to Clean