Now that winter is back, my engine has been back to doing weird s*** like idling at 500 rpm when cold. This also causes the engine to rock side to side, and the tach bounces between 700 and 1000.

I played around with the iacv yesterday while changing waterpump, and that caused it to run like 2,000 rpm at idle. Bad idea. So I was able to turn it clockwise back down and readjust. However, when I do it with the engine running, it doesn’t seem to do anything.

A friend of mine suggesting I turn the idle air control valve, which helped his Acura. But after having it idle at 2,000, I’m scared to mess around with it. Do I need to take it in for a diagnostic test before making any adjustments? I’m tempted to pay Infiniti another $159 for a diagnostic to get it right.

Why do you think your IACV needs to be adjusted? And why would you dink with it without reading the FSM or asking someone who knows?

I'll tell you [later] why it didn;t seem to make a difference, but you gotta quit dinking with things without understanding how they work.

Low cold idle might simply be a plugged orifice in the TB. If your tach jumps from 700-1000, then it's not idling at 500.

Bad motor mounts are likely to blame for engine movement.

Did you buy a scanner yet? Why would you pay a dealer for something you can do yourself?

Buy yourself an early present: https://www.amazon.com/s?k=actron+scanner

I wish I could post a video of what happens lol. Maybe I’ll do that in the morning to get a better idea.

Here’s the thing: I actually replaced the IACV with a salvage vehicle earlier this year, but admittedly I didn’t know how far to turn the screw. I left it as is, and didnt have any issues. But the cold start problem was still on-going. I had previously read elsewhere that a bad IACV can cause the symptoms I’m describing.

The reason why I “dinked” with it, is to see if bringing the idle up a little (as suggested by another friend) would cut the issue.

And yes, it does idle at 500, sometimes 400, 300, 250, and then stall. ONLY in cold weather below maybe 20 degrees. The colder it is outside, the worse it gets. It’ll knock and misfire (check engine blinks). When it’s 90 degrees out (like in Arizona where I bought it...you should know lol), the problem disappears. You’ll never know it does it until the temperatures drop below 60. It gets worse by each 10 degrees. Anything below 10 degrees, the car will stall out a couple of times and I have to slowly press on the gas to keep it running. And pressing the gas doesn’t do much because it’s shaking and barely getting fuel to the engine. Had that issue couple weeks ago in Denver. Have to warm the car up for 2 minutes, then it barely moves once I get into drive.

I know taking it to the dealer is not going to get me much credit here lol, but similar to my rear-suspension issue, I have had 2 shops look at it, say what looks wrong, but then refer me elsewhere. Waste of time.

Also those scanners don’t work lol. I had to go to the dealer to clear my airbag light because the auto parts store and even my own Infiniti mechanic back home in Florida couldn’t clear it.

I am starting to believe this car is just meant to be taken to the dealer periodically lol. No way around it. Notice in the manual, every other paragraph is, “see the dealer”. Check engine light on? Dealer. Windshield need replaced? See dealer. Need a car wash? See your Infiniti dealer for service. I usually have about 5 pages of the FSM open on my laptop whenever I’m doing any extensive work.

Why would you "lol?" What's funny about using a scanner to read the codes that your ECU is showing? That's its entire freaking function. They "don't work?" Ummm, what? I use an OBD scanner all the time. My 21 year old daughter can read OBD2 codes. So, tell me again how they "don't work." I'll wait.

You can't clear an airbag light unless you repair the problem properly. There's a reason for it.

How do you know it's "barely getting fuel to the engine?" You don't. You're guessing.

We don't guess here. We use empirical evidence, gathered by a scanner, coupled with observations, to make decisions.

Aside from some random dude's suggestion, why would you replace the IACV? And why would you mess with the screw?

*sigh* If you're not here to learn, let us know. Those "see the dealer" instructions are aimed squarely at someone like you, and for good reason.

Or, you can keep poking around in the dark, getting frustrated, and blaming someone else.

Wait, but who am I blaming though? I’m just saying what I know. Let me stop you here for a minute because I don’t think I’m getting enough credit where it’s due. I’ve saved this car from death MANY times.

I may not be an ASE certified technician, but this car would have already been in the salvage yard long time ago, if it weren’t for my GUESSES and general mechanical knowledge. Matter of fact, nearly everytime it’s had a near mechanic breakdown, I fixed it. I always refer to the manual. I remember couple of years ago when I first bought the car, I was stranded trying to figure out how to stop the fan clutch from continuing to wobble and fall off into the radiator. No 1 could give a good answer. Since then (and after reading the manual and looking at salvage cars as reference) I’ve replaced the fan clutch and as of this weekend, the waterpump itself...and it’s done just as good if not better than a shop would.

The check airbag light was blinking even after having the clockspring replaced right around this time last year (and that was a b**** and a half to fix because I brought a used one that didn’t work, and never got my money back from it). The light would not go off, even after the mechanic who installed the new clockspring fixed it cleared the code. I also took it to car part stores, and it didn’t clear either. It stayed on for months, until I took it to the dealer who was able to clear the code. The light hasn’t been blinking since, and there was no fault in my airbag system. It simply stored the bad clockspring code, and it could only be reset by the dealer. Have you ever had this occur?

Going back to the IACV valve, before my friend even suggested it, I looked it up myself after having researched common issues for this problem. Yes, I don’t know the exact air fuel mixture ratios and all that technical stuff, but I’ve taken off and inspected the IACV before. Like I said, based on the FSM on this site, it showed a diagram to turn it counter clockwise to raise idle speed, clockwise to lower it. I did exactly that just to see how the engine would respond.

HOWEVER, since then I was able to get it back down to normal idle. BUT, the issue with the tach going up and down, cabin filling with fuel smell, misfiring in below 20 degrees, and engine rocking all ONLY in cold weather persists. I also seem to be having hard time turning over at startup once the car is warmed up. It’s not the battery or the starter because those are both in good working order. This just started at the same time as the waterpump started making weird noises. Maybe I didn’t get it right by turning the IACV a couple turns, but isn’t that what a diagnostic is for?

And the reason why I said the scanners don’t work is because they don’t tell you everything. I had that s*** done when I 1st brought the car. The guy at advance auto scanned the codes, wrote down 5 codes and told me to google it. What the f*** does that tell me? Not god damn thing. I know the FSM does go over each code and what it means, but that’s all still guesses too. Only thing I was able to isolate was the multiple misfire code, which was down to bad plugs and boots...because when I brought the car 2 cylinders were filled with oil due to valve cover/spark seal leak.

And 60,000 miles after I changed all the plugs, I had 1 spark plug break off an electrode while I was driving last August. I didn’t know what the hell happened, but I had to take a GUESS that seemed to point to the issue I had prior. So in a hotel parking lot (this happened while I was on a road trip), I had to change all 8 plugs and boots, to isolate the 1 possible broken spark plug. I took out 5 before I got the 6th one, and the 8th one was close to it too. Definitely won’t be buying Bosch again lol.

But the whole point I’m making in this book of a post, dude give me a break. I appreciate this forum more than any resource for this car, but I can’t f*** come here and ask every single time I have an issue. Sometimes the problem needs immediate attention. It already takes a few days to get a response, and the manual is only as good as one’s experience goes.

And since I’ve had this car, it’s only been the the dealer once for the airbag light, and I’ve only had 2 mechanics touch anything with the engine. All the other times it’s usually me busting my knuckles to fix or maintain stuff.

Even the issue with the waterpump: I came out and started my car one morning and out of nowhere the belts were squealing and then I hear this grinding noise. Then it went away, then came back. Rather than take it to a mechanic who would have me waiting 2 hours, and give me some major bill, I isolated the problem...but couldn’t fix it til I got home (at the time was 1,100 miles away). My guess was right because everything is back to normal and the leak, grinds or squeals are gone. Yeah I f*** up using stop leak, but I don’t think stop leak is what messed it up. It was old anyway.

If you have to demand credit, it's not due.

Good job on the water pump. That's a PITA project, and a great 'starter' job for someone looking to fix something substantive.

Yes, I've had the airbag issue. No need to write a book about it - the simple answer is, it's a federally-mandated thing to require qualified techs to reset an airbag light. Otherwise, you'd have every numbnuts in town fixing front-end damaged cars, stuffing a pillowcase behind the steering wheel cover, and clearing the code. Since you asked, there's your answer.

Know why your IACV "repair" didn''t work? You didn't unplug the AAC. The only function of the IACV is to provide a base amount of auxiliary idle air when ALL other functions are correct. Again, if the orifice is plugged, you can diddle with that screw until you're old and gray, and nothing will change. It doesn't work like a carburetor idle adjustment at all. That's a common misconception - and a good reason to ask and research before twirling the ol' flathead.

You expected a monkey at Advance to help with a diagnostic? For 17 years we've been here doing this. We're here to help, but we don't hand out cookies... and a scanner beats poking in the dark EVERY time. Period. Use it right, and it's a valuable tool - but I can't think of one logical reason (other than a head injury) to resist using a proper diagnostic tool. BTW, get a multimeter as well.

You can't point to a brand of plugs as the reason [blame] for a broken electrode. That's ludicrous.

Now, you should have bought NGK, since that's what your car uses, but identifying a lack of spark on one cylinder isn't hard - you disconnect one at a time, listening for a change. When you disconnect one and nothing changes, there's your failure.

Know why I'm busting your balls? Because 25 years ago, I was you. I know how this story goes.

Fair enough, lesson learned. I won’t be doing anymore “tweaks” until I know exactly what’s going on. Fortunately, it found a way to reset itself (if that’s even possible), and idle is normal now. The cold issue continues, but I think I’m just going to take it to Infiniti at some point for a full look over (something I’ve already done, but I really think there’s some emissions issues going on...), just for the sole purpose of getting a loaner vehicle for a day or 2. I’ve still never had anyone “diagnose” my engine yet. It’s just been all suspension related. And now I’m having issues with delayed startup when warm. The starter seems strong, but it’s taking long to crank over, or it stalls out. My Maxima does the same thing, and a previous mechanic ran a scanner and had me changing out a couple sensors, which didn’t help.

Spark plugs: considering it was already 60k, I went ahead and changed all the plugs and boots at the time. Another plug was already about to break anyway, and the boots weren’t going to be far off. It just sucked because it was a hotel parking lot in 90 degree weather. But I’d take that much more over this freezing BS it’s been lately. I did go with NGK. When I changed them 2 years ago, Bosch sounded like an upgrade.

Anyway, moving forward. Didn't mean to get all defensive. Just a lot to do, work in progress. If these cars have 9 lives, I’m pretty sure I’ve used up about 3 or 4 so far. Previous owners likely went thru the same, which is why it was on Craigslist and letgo lol.

But the good news: it’s driving great now, and I’m still getting compliments often despite the dull rims and peeling paint. The q45 just looks like a mercedes, bmw, and silver spur depending on the angle lol. Next year, I’m hoping for a paint job or possibly professionally mirror shining the wheels.