Ty, I'm sorry but your a bigger problem than the truck's problems at this point because you want to jump to conclusions on a system you don't understand.
You came here for help; we have it to offer but you must listen.
.
You are making the same mistake to last owner made and sold, out of frustration, same as what is happening to you now.
You must see the problems, understand them before any repairs will clear them..
First use a Scanner to see what PIDS are not complete as a start.
And list any codes set.
I can tell you two things right off; one is the fuel evap system has 4 test phases and is very complex and can take a lot of drive cycles to complete providing there are no faults.. On an old truck, parts and hoses may have deteriorated in that system to hinder this PID from completing if at all.
Two, the drive cycle format does not always work for every situation.
Right here on these two items you will get into frustration if you don't take them into account.
On top of this there may be additional issues to clear. You don't know if there is or what they may be, at this time.
You must roll with one at a time and clear them to a good running motor.
There is no other way.
A good shop would have to do all the above if you were to take it to their shop and you expect the same good end result..
It's a good thing your medical doctors do not work out of changing parts, guessing, and frustration or you would never get medical help.
Hint, better not buy a late model vehicle because they are hundreds of percent more complex yet, expecting to do these type repairs.
Give in and do what we suggest so 'healing' can begin..
If you become offended by my attempt to help then I will remain silent after this reply.
Good luck.

 

Ok, here's the location of that front elbow... the tip of the pencil...



On mine (1998), it's a hard plastic line with a little rubber boot at the elbow.. the boot is what wears out..





The rear one is harder to find, and impossible to see... You just have to reach waaaaay back there, behind the intake, under the firewall, and just feel around for it. It's very hard to reach, I hope you have long arms. When I finally found this one on mine, I knew right away that I found the problem. It was so bad, almost put my finger right through the elbow part.




Good luck man, I hope it works for you. It's actually a pretty easy fix, and cheap too, but it's just really hard to reach.

 

heheheh, I wish I could find an old F150 with this problem, and scoop it up cheap...

It's such a cheap fix, if you know where to look!

When I had this same problem with mine, there was no check engine light, but the idle was really rough. A few dollars worth of hoses was all it took... but it took a long time to find those hoses... the internet is great sometimes!

 

I spent over a year looking at and shopping for F150's on craigslist before I found this one. You can look at my posting history to see a few posts I made about trucks I DIDN'T buy. I hope this is the problem. I'm going to go look tonight in the dark and see if I can feel it. Hope my phone will render your pics good when I'm on top of the vehicle feeling around.

Do you know the name of this vacuum line/ what it's for, etc...?
Do I replace the hose, the rubber boot, both, is the whole assembly a specialized part and if so do you know the part number?

For my visual reference, in your 1st pic, is that flying saucer thing below and to the right called the "EGR valve"? I'm 90% certain it is but I also sort of remember that there is sometimes another "flying saucer" shaped part that's NOT the EGR valve. I just want to make certain that if I call that thing the EGR valve, that's what it really is.

I intend to use that as a navigational reference when I go looking for this hose and 90 deg. rubber boot. I'll probably have to climb on top of the engine in order to do this, which I HATE.

 

I'm not sure about the flying saucer, but you might be right ....

In any case, look close at the second picture, and Zoom in... The tip of the pencil is touching that front rubber elbow...

It's a hard plastic line, with a rubber elbow on the end. The rubber elbow part is small, it would fit in the palm of your hand... The other end of it goes straight up, (but you can't see that end in the pic).

To get at it, you'll probably want to remove the main air intake hose where it connects to the front of the manifold... and maybe unplug a couple other wires and hoses too... it's hard to get a grip on it unless you get some stuff out of the way...

The back one is much harder to reach, and damn near impossible to see, but it's back there, I promise... maybe you could stick your phone back there and snap a few pics, it might help.. That back one is a real p.i.t.a. to reach!

 

PS Tyrone, that little rubber elbow was available "off the shelf" at my local O'Reilly's Auto Parts..

I just brought the old one in, and matched it up.

 

....................

 

Tonight I went out and dug around in the engine and I think I might have found a problem, but maybe not THE problem.

I think it's a "PCV valve". Posting this to get confirmation of this. Mounts/Installs on the passenger side valve cover, way in the back by the firewall, has about 3 different hoses coming off of it. See pic below.

Covered in oil, and the thing floats around inside the grommet. It's so loose that I know it's got to be bad, meaning the grommet. I wonder if all the oil has made the valve itself bad too.

 

Thanks Jim you got me jump-started on this thing. I've found the hard plastic line that goes from the PCV valve on the passenger side to the front, towards the EGR valve. The front has a 90 degree bend, which looked/felt good, and the back was a straight piece of rubber which was hard and dry. I don't think that's the leak, I think it's the grommet that seals the PCV valve to the valve cover gasket.

I'm going to replace all 3 tomorrow, I think. PCV valve, the grommet and the straight boot. The other two hoses coming off the PCV valve are gunky with oil and feel really spongy like they are old and rotten. I've seen rubber like this collapse under vacuum and close off. Think a smoke test is also going to happen. I've watched a few Youtube videos and am going to use a metal can, charcoal briquets, leaves and a bicycle pump and hook it to the big vacuum line going to the brake master cylinder. It occurs to me that maybe this vacuum leak could be causing my ABS light to turn on also.

 

The rear one was the first one that failed on mine too... And it sounds like your milage is about the same as when mine went out too..

About a year later, I had to replace the front one too...

So yeah, definitely just replace both of them, and then pop a wheelie!

You might as well replace that other grommet while your at it, but I don't think that one matters as much.

I'm pretty sure that those two vacuum lines will fix everything right up.

 

I think that IS the leak...

In fact, I'll bet you a beer it is...

Don't waste any money on anything else until you replace that little piece of rubber!

When I replaced mine, they didn't have the exact part in stock, so I just used a longer piece of straight hose, and looped it around. It still works fine to this day.

 

Okay so I had a major situation during the day and did not have time to get the parts like I said I would be it's been on my mind so much lately that at 1:00 a.m. tonight I drove to the only 24 hours parts store (which happens to be an AutoZone) in the entire city. The counterman and I had to do a lot of figuring because the PCV valve has this metal tube for circulating radiator fluid and it took a while to figure that out, and why the part on my truck didn't look at all like the replacement PCV valve. Also the plastic "tree" parts included in the replacement were wrong, so instead of installing the part number that was called for, we pulled a generic PCV valve off the shelf because it came with a straight 90 deg. plastic part instead of the multi-hose nipples.

I broke the old 90 off my old PCV valve. The counterman also said that it was the factory original PCV valve, meaning it was old and needed to be replaced anyways. So we replaced both the PCV and the grommet that it fits into and when I started it it ran PERFECT.

For about 5 minutes and then it went back to it's same-old shakey-jake stuff. Not as bad; the idle is much smoother than it used to be, but it's still bad. Now I'm wondering if the PCV tube that goes from the PCV valve to the front where the 90 deg elbow is you talked about is clogged or something. Collapsed, melted whatever. I see the whole PCV tube assembly with both rubber ends (straight, and the 90 deg elbow, and the plastic tube in between them) for sale for like $30.00. I'm tempted to throw money at the problem and hope it fixes it.

Smoke test has still not been done yet. What other options do I have, and what other suggestions are there?

 

Don't over-think it man, just replace those little rubber boots and see.

The hard plastic part is probably fine.

The rubber parts wear out because of all the damn ethanol that they put in our gas these days.

 

With a vacuum leak, the computer richens up the fuel to account for it.
That CAUSES rough idle and even stalling from being TOO rich.
Good luck.

 

So today I think I got some real progress. I think filling the tank allowed the OBD thing to complete, because now the P1000 code is cleared and I have a bunch of new ones. But at least it's something to work with now.

The test was done by Auto Zone and printed out.
I assume they arrange the codes in order of most-important to least important.

P0174 - Fuel System Too Lean (Cylinder Bank 2)
P0420 - Catalyst System Efficiency Ban 1 Below Threshold
P1131 - Lack of HO2S-11 Switching, HO2S Signal Low Input
P1151 - Lack of HO2S-21 Switching, HO2S Signal Low Input
P0306 - Cylinder Number 6 misfire Detected

Auto Zone's "Big Suggestion" is to replace the Fuel Filter and that's my main question on these new OBD codes. If the fuel was restricted by the fuel filter then why is only Cylinder Bank 2 too lean? Seems like all the banks (I assume there are two) should be lean, since the fill filter is central to both.

My mechanic friend agrees and says I should run Sea Foam through the engine first, before replacing the fuel filter or looking for something else to try.

I'll research the other codes after posting this. It's possible that the #6 cylinder misfire was due to the old spark plug wires. One of them was routed improperly, and had actually melted against the exhaust manifold on the front driver's side. I'll have to find a picture showing the pistons and which one is numbered which.

Because some of these codes may have happened before the spark plugs and spark plug wires were changed, and/or after the PCV valve was replaced, I'm going to clear the codes and get another reading to see which ones persist.