Hello…
My 2001 Nissan Pathfinder has a problem when idling. The idle speed will slowly decrease until the car almost cuts off; then, it will usually quickly recover and restore the idle speed to something appropriate. However, sometimes it will actually stall and cut off. This will happen cyclically about every 15 seconds or so.
The problem is exacerbated by cold temperatures. While the problem does occur during warmer temperatures, it is significantly less noticeable.
Also, if the A/C compressor is engaged, the symptoms are not as severe. So, in the summer, as long as the A/C is on, the problem is somewhat sufferable.
Specifically, this is what typically happens. I pull up to a stop sign or red light. If I have to wait for more than a few seconds, this cycle will start to occur. I watch the idle speed start decreasing. Then if I have to wait much longer, the car will either recover spastically or cut off. Then, the cycle will begin again.
Interestingly, this does not occur until the car reaches “normal” operating temperature. For example, when I warm the car up during cold weather, it works fine while the car is first warming up. Then, once I get on the road, the problem begins to occur. Unless I let it warm up for a long time, in which case, it will occur in driveway, before I start to drive the car.
It would also appear that it is influenced by whether it is in Park, or in Drive and the brake is pressed. So, when waiting at the afore mentioned red light :-), if I put it in park, it will do better. But, once I depress the brakes, the idle will begin to decrease. I assume that this is because of some input trigger informing the system to affect the idle in some way? At least, that is my assumption.
The maintenance history of this issue is very frustrating. I have been to the dealer for this several times, as well as a local “import auto” mechanic shop. I have spent a small fortune “fixing the problem”. When I first take it in to a place, they usually can’t reproduce the problem. Which simply means they don’t take the time to bring it up to operating temperature. So, I wind up having to “show” it to them; meaning, when I pull in to the shop, I say something like, “excuse me, sir. Does this sound right”? This typically elicits responses like “hmm… that’s bad”. I guess I should expect that, since I live in the “show me” state. 
This also usually elicits a long soliloquy, detailing how “hard” it is to fix idling problems nowadays. These sad tales usually include a historical litany of pre-industrial age issues and dilemmas that only Henry Ford himself could have envisioned. Their intent is to infer that, for some reason, idling issues can no longer be resolved without the aid of seven or more ancient scroll writings, a week in Tibet and the use of some arcane translation tools; likely, requiring at least one cross reference with the Rosetta Stone. I imagine that these explanations are proffered for my sake, in order to mitigate the eventual “let down” for when they can’t solve the issue, which has always been case.
Unfortunately, since the problem is only really bad in cold weather, I tend to just get frustrated after I leave and the problem is not fixed. Subsequently, I tend to just ignore it until the current cold weather snap clears; then, I just forget about it until the next cold snap arrives. Living in Missouri, cold weather of this nature usually lasts just a few days to a week or so. So, by the time I have a chance to get back to the last guy that didn’t solve the problem, the temperature (and my temper) is much better.
The dealer has tried numerous things, but explains that fixing it is a process of eliminating a laundry list of possible issues. Unfortunately, they are only about 25% down “the list”. 
However, now the problem is getting worse. I am now starting the third winter with this problem and it is getting really bad. We took a trip over the last weekend and temperatures dropped into single digits. It constantly cut out at almost all red lights. This problem is intolerable! Arggghhh!
I can’t keep spending money TRYING to get the problem fixed. I love my Pathfinder, but if this isn’t resolved I am going to torch it or something. Otherwise, before I go back in to get this fixed, I want to have some idea of what needs to be done, so that they don’t just keep working through “the list”, while I move to the poor house.
I have recently heard about problems with comparable models and their “ejector valve(s)”, where similar symptoms seemed to occur. Is this relevant?
Likewise, thanks to a CarTalk link, I just came across this 2007 recall notice (“http://www.cars.com/go/recalls/rclMain.jsp?year=2001&mkid=36&mdid=335&pt=&fill=display&record=0&aff=cartalk”). Could this be a factor? I am not sure exactly when in 2007 my Nissan was manufactured, so it may not apply?
Any other ideas?
Unfortunately, I know very little about cars. Although, I do own a wonderful Bosch coffee maker that is actually manufactured by Porsche. It says right on it, “Designed by F.A. Porsche”. So, I do have that going for me. Although, disclosing this fact to my dealer’s mechanics has not seemed to motivate them any appreciable amount.
Thanks much for any help… “Exasperated in MO”
Perhaps if you told us what the dealer and the other mechanic have done in order to eliminate the idling problem it would help.
We don’t need to recommend things that have already been tried.
Has any one cleaned or replaced the Idle Air Control (IAC) valve? Has anyone tested for vacuum leaks?
Hello, mcparadise. Thanks for the response.
Yes, one of the last things that the import auto mechanic did was to clean some valve. I am pretty sure it is the one you are asking about, although I think they just called it the “control valve”. I am really sorry, but it has been a year (last winter) since they cleaned that valve. I will dig out the paper work and try to decipher it tomorrow (Tuesday).
Also, I am pretty sure I asked them about a possible vacuum issue and they said they would check it. Since they never said there was a vacuum problem, I guess I just assumed there wasn’t one. Perhaps they didn’t check it and I just thought they did. Again, that was a while back. I will ask them about it again this time.
Thanks again for the feedback. Sorry I couldn’t provide more info. I was hoping the symptoms might describe a very common, or at least obvious, problem, so that I could make sure the dealer checks that out. But then, if that was the case, my dealer would have fixed it already.
Obviously, its back to the dealer for me. Here’s hoping they find it quickly (and cheaply) this time.
Your problem is worse when the weather is very cold, yes? If those mechanics are taking the vehicle into the nice, warm, garage and doing the troubleshooting (IF they are doing any troubleshooting), and can’t duplicate the problem, duhhhhhh!
The dealer has been, er…what’s the word?.., anyway, “ineffective”. Ask around of friends and aquaint, for some mechanic they know who can handle this type of problem. This isn’t an unsolvable problem. It just needs the right mechanic, with the right mental tools.
Hellokit, you hit it right on the head. Obviously, I took it back to the dealer yesterday. They have a new service manager. I pulled it in and made sure he waited until I showed him the problem. But, just like you said, in the warmer garage the problem was not as bad. Go figure! However, it had gotten so bad that it did occur, just not as bad.
Well… After MUCH begging them to PLEASE find the issue this time, they were able to track the issue down to a bad “mass air meter”. Go figure. So, after a new mass air meter, a new air filter a little over $700, my Pathfinder is happy again! Hallelujah!
Bad money timing given the season, but at least they finally found it. I love my Pathfinder, but had really reached my end with this problem. They did gave me some discounts, given that I had been in for this several times before, which was appreciated.
Thanks for the input.