"Sometimes At idle there's a very very faint knock/metal to metal noise in the engine. Like the metal to metal/knock will sound for 10 seconds then go away. Then come back."

Sounds like intermittent lifter tapping. Faulty lifters can cause a tapping sound, which also means they are probably not opening the valve as far or any as it should. This can also cause an engine shake. Not sure if you've done any work in that area.

 

I haven't done work like that. pretty sure its the power steering pully hitting metal. There is play in it. gets very loud at 2000-2500 rpm. I have an audio track if someone wants to take a listen

 

Yes, to the latter, fan clutch will do it as well

Look at long term fuel trims(LTFT) see what it says
Fuel trims should go up into the teens and even 20s when accelerating
+20 fuel trim is not indicating "lean", it means computer is adding more fuel, its related to fuel injector OPEN TIME and nothing else, computer is opening injectors 20% longer than it would have calculated to satisfy drivers input

Do the IAC Valve test

LTFT is an average of STFT over many days or months depending when they were last cleared, -10 to +10 are normal range, codes are set at about -15 or +15 if it happens long term

 

at idle the long term goes up to like 15 and 23 when revving. Wanna listen to the audio track of the power steering pulley? I think its the power steering pulley. If it is, its hitting metal most likely.

 

here it is

 

If it's the P/S pump, it is easy to find out. Take the belt off and run the engine for a minute(not long or can heat up) to see if sound still exists.

 

to make this easier can i just take the belt off the crank pulley so i dont have to re position the belt on everything?

 

Guess what. No noise when belt is off. Engine was real smooth. But i think the engine smooth part is because belt was off, or is it because the power steering pulley isn't hitting the engine?

 

It would seem then you have something belt driven that's lugging your engine. A/C compressor will do that while engaged to a degree which is normal, but when they start going bad, they will make racket and can begin to lock up. P/S pump can go bad as well. You can usually feel that happening when it gets tougher to turn the steering wheel, or the steering jerks while turning it. Both are pumps essentially and they have bearings that wear down. Water pumps almost always leak first before they fail completely. The circuitry in an alternator is more likely to fail before the bearings in my experiences. The idler pulleys are easy to check by hand.
If your P/S pulley were hitting the bracket it was mounted to, you should be able to see tell tale signs of such, like a wear spot on the pulley or bracket. While it's actually running, looking at the pulley spinning, it would appear to wobble or something. If you have something belt driven lugging the engine bad enough, it would also cause excessive wear on the belt and maybe even burn it up.

 

Glad you found the vibration, good work

Check the fan clutch for wobble, spin water pump and other pulleys by hand so you can hear/see what they sound like, or are binding

Can't spin power steering pump or AC Compressor by hand so its a best guess if you think it should be replaced

 

So having no fan belt on makes the engine smooth on all cars because theres hardly anything running? And you say the play in the p/s pulley cause engine shake? I'm skeptical that this will fix my problems especially the gas mileage but i have the part and i'm gonna install it tomorrow.

 

???

No engine should run smoother with fan belt off UNLESS there is a problem with one of the accessories

Not sure where you read that but its very very WRONG, right up there with Back Pressure and Alternating Dual spark plugs, lol

It is "possible" you could have a engine issue that can't take a 6 horsepower load, what accessories draw from engine, but that's a long shot, and you would certainly notice that more when driving i.e. lack of power, not at idle so much

 

Well it did run buttery smooth with it running for the 20 seconds it did lol. But good I hope this one little pulley fixes this engine shake. Is it like a balancing issue that causes the engine do do this with play in pulleys?

 

Well yes, if you spin something that's not balanced it will vibrate and anything connected to it will vibrate, in this case the engine

 

Do you know the trans cooler line nut size? Also when I hooked up the tool to the pulley and rotated it really hard there was no click noise to indicate it was coming off. I think i was just stripping the nut on the removal tool.

 

NVM i got the bolt size. I found something interesting though. I hooked up my scan tool and saw the long term fuel trims didnt move at all. Completely frozen then bank 1 fuel trim would move 1/2% up then back down every 10 seconds or so and bank 2 was completely frozen. But i would cut the truck off and start it back up the numbers would be different but frozen. Whats going on ?!?!?!?!?

 

O2 sensor feed back only works after engine has warmed up for 3 to 5minutes, depends on outside temp, this is called Open Loop operation

An O2 sensor needs to be heated above 650degF before it starts to work
So computer runs "Choke" mode until it can get feed back from O2s
So fuel trims don't change much, if at all

When O2s start to work and computer can adjust fuel trims, that's called Closed Loop

 

I apologize for bombarding you with crap but i think have a vacuum leak. LTFT 16 and 10 then press on accelerator LTFT go to 5 and 5. I will check later again.

 

I did the iac test and the engine rpm only dropped by 100 and idled at 900. This was on a cold engine

 

Have to do the IAC Valve test on warmed up engine, but does read like vacuum leak if it only dropped to 800rpms, when cold engine should have stalled instantly because computer is running Choke Mode

 

Let truck idle for 20 to get warmed up then drove 5 miles and let it run then unplug iac no change. Even when truck was warm the fuel trim numbers were barely moving as well

 

You have a small leak if idle didn't drop to 500rpms with IAC Valve closed, assuming a Motorcraft or Hitachi IAC Valve, these are solenoids so when powered off they close
3rd party IAC Valves can be stepper motors so stay at the same place when powered off

 

I have aftermarket one. Duralast from autozone. part# tv229

 

You can pull it off, disconnect 2 wires
Turn on the key
Plug 2 wires back in and you should see the valve inside move open, only moves 3/8" so not a big movement, but thats wide open, computer does this for startup, key on
Unplug the wires and it should close again
Repeat a few times to make sure its opening and closing OK, if so then you do have a vacuum leak
OR............

On the throttle linkage is the "anti-diesel" screw, looks like an idle screw but everyone knows fuel injected engines can't use idle screws, that the point of IAC Valve

If someone adjusted the anti-diesel screw then IAC Valve can't do its job as it should
Same test as before, warm engine idling, IAC Valve unplugged
Turn anti-diesel screw 1/2 turn counter clockwise, unscrew
If RPMs drop then someone HAS messed with it
If no change in RPMs then turn it back to where it was, you have a small vacuum leak

If RPMs did drop keep turning screw until engine is barely running, 500rpms, and that's it, its been reset, and you have no vacuum leak, just irresponsible previous owner, lol

 

where is the screw? idk what it is