I notice lately that I been getting low idle especially with the temp getting colder. When I'm at a traffic light the idle would sometime drop below 500rpm and I would need to rev it to keep it up. Or sometimes the idle would jump up and down which I can't figure out why. This problem never occur before I install the sc and all maintenance on my car is up to date.

 

I have the same problem and some people on the org say to clean your IAC valve i havent got around to trying it yet. Im going to take my car in to were i get it fixed because they say it could be a small boost leak, i just want to make sure before i clean the IAC valve.

I wont be taking the car in for a month or two so if you decide to clean your IAC valve let me know if it fixed your problem,if i change my mind and clean mine before i take it in i will let you know if it fixed the problem

 

Do you have any monitors?/ engine management?
Wide band afr/fuel psi/ oil pressure/boost/vacuum gauges?
That way we can tell
you may just need to adjust your base idle/clean iacv

 

Im having the same problem well kinda but with mine the car shuts of at low idle. I talk to my cousin and he said its probably my BOV. Cause with the HKS SSQV it doesn't stay open while idleing so less circulation with air. But yea you should get a wideband. I got mine the same as accourdingtou but didn't have time to hook it up. I think I will later on this week.

 

I seriously doubt it has anything to do with the IACV. His car ran fine when it was stock, and that was a very short time ago. And he said it’s fully maintained. I assume that means his IACV is clean or pretty clean. However, a clogged/dirty IACV would cause the symptoms you described. IMO, I think it's caused by something that's part of the SC system you recently installed. ie BOV, small vacuum leak etc. Also, your MAF might be dying. 5th gen MAF’s are known to be sensitive.

The below info pertains to 4th gens. Not sure if it applies to you, but it might.

You may have a bad Engine Coolant Temperature Sensor (ECTS) or a problem with the ECTS harness/connector.

Try wiggling the ECTS wire and harness while the engine is idling. If this prevents the car from stalling, then you may have found the source of the problem. Then, have the mechanic test your ECTS with an ohmmeter.

The ECTS is located in the water outlet tube close to the engine end of the upper radiator hose. There are two sensors in that area. The one nearest the hose is for the dashboard temperature gauge. The ECTS is right next to the the gauge sending unit. Check out the Haynes repair manual for a picture of these sensors.

With the engine cold, disconnect the ECTS and measure its resistance. Reconnect the ECTS, start the engine, run it until fully warmed up. Stop the engine, and repeat the resistance measurement. The "warm" reading should be a much lower value than the "cold" reading.

The manual gives these specs:
Engine coolant temperature 68F, ECTS resistance 2.1 - 2.9 Kohms
Engine coolant temperature 194F, ECTS resistance 0.24 - 0.26 Kohms

 

My car already have the updated 5gen MAF so I don't think it's that. I will check to see it's the IACV and if clogged/dirty or not. Do u know where it's located in the engine dept? As far as bov I got a greddy rs one which seem to be working fine. I checked all the tubing and vacuum but don't see any leaks.

 

Assuming you're asking where the IACV is...find your TB, go along the intake manifold about 4", look right and you'll see the IACV bolted to the side of the intake plenum. Removal and cleaning is easy. There are several posts in the stickies (4th and 5th gen forum) which show pics and have detailed instruction on how to remove and clean it. It's pretty darn simple.

What is an updated 5th gen MAF?

 

If the idle drop below lets say 500 and then jump 1200 - 1500, and sometime the car die on a street lignt or stop sign, there is a good chance that it is the IACV. When it happened to me on my 2k1, I didn't bother to clean the IACV I just bought another one and it cure the problem.

 

Nissan had a updated version of the MAF for 5gen maxima which was stronger than original. My original never had any problem but I swap out for the updated one anyway. I will check on the IACV to see if it's dirty/clogged and clean it. Then will let you guys know if this solve my problem.

 

Hey guys I didn't have a chance to check out my IACV but I did get a chance to check out my throttle body. I notice it was dirty so I cleaned with some throttle body cleaner. The last few days when I drove my car I notice my low idle seem to went away. I will run my car for the next couple of days to make sure my low idle goes away. I will still end up checking on my IACV to see if dirty/clogged but as of now my problem is fixed.