Re-reading the posts & thinking about this some more, did the high idle, loud whistling & lean codes come about suddenly after some event????

 

Here is link to video https://1drv.ms/v/s!AiWaaaEEuA2A6E64rqloKUwEgE9m
About 1 minute in the whistling/whining starts. I turned engine on and off using remote control in case that matters. I was wondering if remote start was
messing with the idle. Notice the idle speed seems normal in the video. That speeds up when I put it in drive or reverse.
There were no recognizable events prior to high idle starting about a year or two ago. Just this fall the whining and the obd2 codes started.

 

Just another thought, the worst noise is around 8 degrees, but this morning it is only 3 degrees. As the video shows the whistle was not that bad. But I took it out for a drive and the whistle returned after warmup.
It is definitely throttle driven, not engine rpm. It is like a turbo whistle. So that would rule out bearings or other engine rpm dependant items.

 

Ok, that video / audio was good feedback. To me it sounds like the high pitched whine is coming from the Passenger side Top Front, Alternator area seemed to me to be the loudest. Maybe get the listening hose out again, or something like a long wooden broom handle & put one end on the alternator frame, the other end to your ear, so the wood is conducting the sound, to try to determine if thats where the sound originates. Could be water pump, or serp belt tensioner, or idler pully bearing. Doesn't sound like a slipping belt screeching sound to me. More like a bearing, or maybe alternator slipring brushes kind of noise. In any case don't walk away from it, try to locate where its coming from & check that item out. Maybe loosen the serp belt & rotate & push / pull the alternator pulley. It should not freewheel rotate, nor have any in / out, back & forth, or wobble play in its bearing, nor feel or sound rough when rotated, or moved to check wobble play. A non worn out bearing will be a little snug but smooth to rotate. Check each belt driven accessory pully close to the alternator for the same kind of play or feel & let us know what you find. .

 

Ok so that was a helpful exercise. I was able to hold the tensioner down with two wrenches in tandem and have two hands free. The idler pulley has wobble play in it. The alternator seems ok according to your instructions.

 

Ok, thats a good find & feedback. So replace the idler pully with a quality part & see how the noise problem goes. You may have more than one problem, so take your time trouble shooting to find & fix them one at a time, so your not tossing parts at the problem on a hunch.

 

Did any of the idle problems come about After the remote start, or any other aftermarket add-on installation???

 

Replaced the idler pulley but that was not the answer. Got a mechanic's stethoscope and found the noise coming from the power steering pump.

 

Attaboy, another good find & feedback on the noise source. The idler needed to be replaced with the looseness you found in its bearing, so look at that finding as preventable problem maintenance, as if / when it finally seized, it would have ruined or broken the serp belt & Murphy's Law says that would probably have happened when going at throttle up to merge in traffic!!!!

Anyway let us know what was going on with the power steering pump, like was it because the fluid was low & aeration was taking place, or was it a internal bearing problem??? If the fluid was low, it likely means there is a system fluid leak somewhere, as the P/S is a Closed system & isn't supposed to use fluid, If no outward leak signs, look / feel at / behind the accordion boots for steering rack end seal, for leaks, if fluid is found behind one or more of the boots. If the pump bearing was going out, maybe it was loading the engine & causing the idle speed to jump around as it loaded & unloaded the engine??? So will be interesting to hear if the idle woes are fixed when the power steering pump noise anomaly is put right.

All this trouble shooting just to find the noise source & put it right, then back to the lean codes for both cyl banks & what the root cause is for that woe. With luck, maybe its responsible for the idle problems too, so you might fix both problems on that trouble shoot. SO, keep us posted on how the trouble shooting & repairs go. More rambling thoughts for consideration.

 

Noise sources can be evasive as they transmit through other objects. There are also multitude of noises of differing frequencies. I heard with mechanics stethoscope the noise in the alternator very loud just coinciding with time of loud shriek from engine cimpartment and same frequency. I've also heard it on the exhaust manifold right side of engine. So power steering, alternator, exhaust manifold...
Then there is the obd2 codes coinciding with loud shriek at lower temperature (engine light stays out in warmer weather).
Given that I have to give the truck back to the owner soon (I borrowed it to get to his job sites and do maintenance) I will likely advise to reset the Mil in the spring and wait until noise source becomes more obvious.
If it was an easy job to tighten the intake manifold bolts I would do it as a test but I'm not sure of the procedure.

 

Was the power steering reservoir fluid low, or was it aerated with lots of air bubbles in it, or look or smell cooked, or otherwise look compromised????

 

The power steering fluid was exactly on the full line but it looked brown color no bubbles. I would like to refresh it (turkey baster method).

 

See any metallic glitter in it, or does the fluid smell cooked??? If its never been changed / flushed with new fluid, probably a good idea to get as much of a quality new fluid in there as possible & see if the pump noise changes, or gets better.

 

When I flush my power steering, I raise the wheels off the ground so they can be turned lock to lock. Then loosen the pump return line at the cooler to drain the pump reservoir of all old fluid & crud, then plug the hose with a round shaft screwdriver, so I can re-fill the reservoir with new fluid. Then add a scrap piece of tubing to the cooler output, the hose loose end in my catch container. Disable the fuel pump so the engine won't run, while having my helper crank the engine & Slowly turn the steering wheel lock to lock, while I keep the pump reservoir topped up with new fluid. This flushes the pump, lines rack & cooler with new fluid, If I get my fluid open & handy to grab & ready to pour, I can keep the reservoir full so the fluid doesn't get aerated, as it can be a pain to work out if we let the reservoir level get low & the pump churn in air bubbles. Anyway I pump out a couple of qts so the system gets a good flush.
Even with 30K PS flushes, because I've had intermittent PS boost drop-out problems on both the 99 Ranger & 94 Taurus, I added a in-line Magnefine filter to both systems PS return line about 12 years ago & its Stopped both PS systems boost drop out problems. So if you come to having that kind of trouble, consider a good quality inline filter in the PS return line after the cooler, its worked for me on 2 vehicles. More thoughts for pondering, let us know how it goes.

 

The screeching noise is definitely the alternator verified with a mechanic's stethoscope. The alternator is generating a lot of noise energy as the decibels could cause ear damage it is that loud a screech. My theory is the poweful noise waves are passing through the engine through the alternator mounting bracket and temporarily vibrating the intake manifold against the engine and letting air in. I could be wrong about that, but it sort of explains everything.
Perhaps alternator bearing lubrication is getting dry and it will get worse.