Unexplained idling issue

[2001Pathy]

Please tell me someone else had run into a wonky idle with their 2001 Nissan Pathfinder. I have had the mass air flow sensor replaced recently and it seems as if the issue has crept up since then. The weird thing is, I only run into problems when its 20 degrees celsius or warmer?

 

The truck will run just fine and then it will all of the sudden the rpm's will increase. It doesn't impact my driving, its when I'm sitting at a red light or shifting out of drive into reverse that I get a little concerned. Rev's will fluctuate from 1250 - 3000 when sitting in neutral, when sitting in gear it will rev around 1000. Typically the truck will idle at 750 or so?

 

Solutions?

[Simon]

IAT sensor? (Intake Air Temperature) I believe they're located on the air intake tubing. Otherwise, check that the MAF wiring is all in good condition, (not frayed, or broken at the connector) and check that the filaments in the MAF sensor are still intact.

[5523Pathfinder]

First of all, Welcome to NPORA! The caR50 community has been under fire lately, so make sure your forcefield is up.

 

 

Anyway, were did you have the air flow meter replaced? what you may have to have performed is the closed throttle position relearn and the idle air volume relearn. The closed throttle relearn is easy. Dit in your truck and put the key in the ignition and turn it on(dont start the engine), count to 10 slowly, the turn the key off and count to 10. Do this about 20 times and it should be set. It may take less than 20, but if you dont do enough, it wont reset. The idle air volume relearn is a bit more difficult, but you can do it. Follow these steps...

 

1. Turn ignition switch "on" and wait at least one second.

2. Turn ignition switch "off" and wat at least 10 seconds.

3. Start engine and warm it up ton normal operating temperature.

4. Turn ignition switch "off" and wait at least 10 seconds.

5. Start the engine and let it idle for at least 30 seconds.

6. Disconnect throttle position sensor harness connector (brown), then reconnect it within 5 seconds.

7. Wait 20 seconds.

8. Make sure that the idle speed it within specs. If not, the result will be incomplete. In this case, find the cause of the problem by looking for any problem the the throttle valve, PCV valve operation, air leaks and anything that looks incorrect.

9. Rev up the engine 2 or 3 times. Make sure that idle speed and ignition timing are within specs.

 

*idle speed M/T: 750 +- 50rpm

A/T: 750 +- 50rpm (in "P" or "N" postion)

 

Try it and see if it helps. If not, and you had it replaced at the dealer, you may have to take it back.

[2001Pathy]

Wow...this is wicked! I had the air sensor replaced by a Nissan Dealership here in Edmonton, AB. I'll take both of these recommendations and let you know how I make out.

 

Thanks again!

[Slick]

welcome to the family!

[Precise1]

Wow...this is wicked!

 

Yeah, it's handy having a Nissan mechanic member who doesn't mind taking a moment to help.

 

Welcome, by the way.

 

B