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AMEDEE
AMEDEE, NISSAN MECHANIC
Category: Nissan
Satisfied Customers: 24390
Experience:  ASE certified tech ADVANCED LEVEL PERFORMANCE. Wisconsin certified emissions state inspector
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I have a 96 pathfinder.always runs good going down the

Customer Question

I have a 96 pathfinder.always runs good going down the road.lately would not restart when engine was up to operating temp. I replaced the distributer, that did not fix it. next I replaced the MAF , that seemed to fix the restart problem,but now I have an idle problem = low rpm ,rough running.i have tried to adjust the TPS ,it will run fine for a few seconds then slows to low rpm and runs rough. maybe knock sensor?
Submitted: 10 months ago.
Category: Nissan
Expert:  AMEDEE replied 10 months ago.

Hello and welcome! My name is ***** ***** I can assist you with your question. The knock sensor will not cause this idle issue you are describing.

Expert:  AMEDEE replied 10 months ago.

This low engine idle or rough running condition is either caused by an air or a vacuum leak or a stuck open EGR valve. I would start by checking for air/vacuum leaks first and then go after the EGR valve. Look close by the intake manifold gakset and throttle body gasket as well as all of the vacuum hoses and lines and replace any as needed.

Expert:  AMEDEE replied 10 months ago.

You can check the signal from the mass air flow sensor. If it is low at idle, this indicates a vacuum leak. The output voltage signal and should read about 1.3 volts at warm idle.

Expert:  AMEDEE replied 10 months ago.

Also, check the throttle body to ensure it is nice and clean and it is not sticking. In addition, check the TPS voltage to be sure it is reading correctly at idle and that the voltage is nice and steady with the throttle plate closed when this idling issue occurs.

Expert:  AMEDEE replied 10 months ago.

And be sure to check the fuel pressure regulator for leaks. Remove the vacuum hose and if there is any fuel present, the regulator is bad and will need to be replaced.

Last but not least, if all checks out good and there is no air or vacuum leaks, then I would suspect a bad/lazy idle air control valve located on the side of the throttle body. They can get slow over time and stick closed resulting in a low idle or stalling condition.

Expert:  AMEDEE replied 10 months ago.

I am glad I can help!

It has been a pleasure working with you. Please dont forget to honor your good faith deposit by rating my answer as "Excellent Service" for assisting you today.

Please let me know if you have any further questions.

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