Mechanics

99: ENGINE IDLES UNEVENLY AND VIBRATES.

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
AD
Avatar
Fuulhouse
August 8, 2012.



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

Saturntech9
Aug 8, 2012.
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

Tiny
Fuulhouse
Aug 9, 2012.
So does your scan tool read live data?

Saturntech9
Aug 10, 2012.
I am not sure. But I ll check it. What should I look for?

Tiny
Fuulhouse
Aug 15, 2012.
See what the tps sensor reads while at idle?

Saturntech9
Aug 15, 2012.
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

Tiny
Fuulhouse
Aug 22, 2012.

AD