Altima 99 Engine idles unevenly and vibrates.

Tiny
FUULHOUSE
  • 1999 NISSAN ALTIMA
  • 133,000 MILES

My engine revolution is uneven, fluctuates between 900-1000rpm when starting from a cold temperature. When its temperature is higher, maybe after driving around for sometimes, it starts and stalls. Also, when on idle, it vibrates. OBD-2 scanner returned MAP sensor and Throttle position sensor problem. I ve replaced the throttle position sensor but it still does that. I did not replace the MAP because I dont its location and becos I read that most times, the MAP malfunctions because the throttle is bad.
I will appreciate any help on the MAP location and any other help to solve this. Thanks

Do you
have the same problem?
Yes
No
Wednesday, August 8th, 2012 AT 3:46 PM

6 Replies

Tiny
SATURNTECH9
  • EXPERT
  • 30,281 POSTS

Please post the exact code numbers not code descriptions. That will make it a lot easier to help you.

Was this
answer
helpful?
Yes
No
Wednesday, August 8th, 2012 AT 3:49 PM
Tiny
FUULHOUSE
  • MEMBER

The codes from OBD-2 scanner are p0120 - Throttle position sensor, p0105 - MAP circuit malfunction, p0443 - Evaporative Emission control system purge control valve circuit. I ve taken the car to my mechanic who said the MAP sensor is ok. But it still does that. I need to add that the car surges forward when changing from Gear 1 to 2. Thanks

Was this
answer
helpful?
Yes
No
Thursday, August 9th, 2012 AT 1:48 PM
Tiny
SATURNTECH9
  • EXPERT
  • 30,281 POSTS

So does your scan tool read live data?

Was this
answer
helpful?
Yes
No
Friday, August 10th, 2012 AT 11:10 PM
Tiny
FUULHOUSE
  • MEMBER

I am not sure. But I ll check it. What should I look for?

Was this
answer
helpful?
Yes
No
Wednesday, August 15th, 2012 AT 1:36 PM
Tiny
SATURNTECH9
  • EXPERT
  • 30,281 POSTS

See what the tps sensor reads while at idle?

Was this
answer
helpful?
Yes
No
Wednesday, August 15th, 2012 AT 4:32 PM
Tiny
FUULHOUSE
  • MEMBER

While at Idle, the tps read 0%, while I accelarated with the gear position in park, the tps still read 0%. Intake MAP showed 1kPA. Thanks

Was this
answer
helpful?
Yes
No
Wednesday, August 22nd, 2012 AT 12:27 PM

Please login or register to post a reply.

Other Engine Vibration Questions