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1999 Nissan Altima Repair Question


Topics covered: Sensor, Map sensor , Engine.
Mileage: 133,000 miles.

Asked on August 8, 2012

99: engine idles unevenly and vibrates.

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
Avatar Asked by fuulhouse

Answer

Replied on August 8, 2012

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

Tiny Answered by saturntech9 (expert)
23,388 answers provided
Replied on August 9, 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 Response from fuulhouse
1 question asked
Replied on August 10, 2012

So does your scan tool read live data?

Tiny Answered by saturntech9 (expert)
23,388 answers provided

Replied on August 15, 2012

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

Tiny Response from fuulhouse
1 question asked
Replied on August 15, 2012

See what the tps sensor reads while at idle?

Tiny Answered by saturntech9 (expert)
23,388 answers provided
Replied on August 22, 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 Response from fuulhouse
1 question asked