Matt,
IAC=idle air controller (i think) anyway it controls your idle.
It's right next to or on top of your throttle body. Go here http://www.fordf150.net/howto/throttlebodyclean2.php and you'll see a detailed "how to clean your TB and IAC."
Before you try to clean it, tap on it a few times. You might want to use your own tools this time. Save the sears trick for your complete rebuild. Does sears sell motorstands?

 

I found My problem.
I followed the hose from the pcv to the back and sure enough that rear elbow
was melted almost all the way through.$4.00 and 2 minutes later,fixed.
runs smooth,idle about 650-700.
However,the way it was, I had a bit more get up and go,I mean It would light up the tires to barley tap on throttle.But it runs right now,and thats good CEL is OFF finally.

Mine never died,every once in a while it would idle down real low like it was going to,but would come right back up.

I tried the carb cleaner spray trick,and did nothing because of where and how it was leaking,there was no way to spray that direction.



Now to check on the intake mod(the free one you can do in an hour)
I know the 4.6 has a silencer,just gotta find out what to do for my 5.4....


1997 F-150 XLT Supercab 5.4(330 ci)

 

What do you mean by the "rear elbow"? Where can I find it? I too tried spraying around the the air intake, etc with no luck... I think the booster was my biggest problem, but maybe I too should check the rear elbow... Is that the piece behind the intake? Someone sent me some pictures showing something like what your describing... Thanks!

 

yeah...follow the hose from the pcv around behind the intake.you should be able to feel the rubber elbow.
mine was melted almost all the way though.



1997 F-150 XLT Supercab 5.4L (330 c.i.)

 

I have a 96 F150 4X4 300cu in 6cyl. I got the same exact deal going on. Only I was dumb enough to take mine to the Ford dealer . Well after a new mass airflow and new plugs / wires guess what? Still got check engine lite and codes. So we go back to the dealer and get new oxigen sensors and guess what? Still got check engine and codes. So we go back to the dealer and get a new gas pressure regulator and a couple of vaccuum hoses. GUESS WHAT Still got check engine lite and the codes. The Ford dealer says they are backing away from the challange because I have an after-market high flow cat conv. WHATTA COPOUT. So don't spend $1300.oo like I did Just wait untill some one at F150.COM comes up with the real fix. I'll be stayin tuned.. GOOD LUCK !

 

Can I get in on this posting? Good job in finding and fixing your problem. Now – my 4.2L has the code for bank 2 and my check engine light has been on. Went through the same thing you did at Auto Zone. They wanted to sell me the sensor but I’d like to eliminate the PCV hose first. I pulled the PCV valve out and cleaned it and the light went out for about a month and came back on.
My question: how do you see and reach the back of the intake manifold on this motor?. I can hardly get to the PCV valve. I can run my fingers part way back to the manifold following the hose but I cannot reach the connection to the manifold. Can you get to it from the bottom? Do I need to remove something from the top? I take it that this is the location of the rubber elbow that cracks or melts. On a 4.2, is there an elbow? Does the elbow have a hose clamp or does it just slid on?
Thanks a lot for the help with this.

 

Hey - I have a 4.2. My bad elbow came from under the IAC area. This rubber elbow slides on and off; no clamps. It was easy to remove. I needed to remove the cover to the throttle lever to get "easier" access. I also had a major HISS sound so it was easy to find. Once fixed, my truck is back to running great!

*** I have a temporary plug (silicone and tape) for that rubber elbow but I'm looking for a new replacement. My problem is that the elbow has a small end and a larger end. It's causing me a headache. Autozone nor Napa could help me.

Anybody know where I can find a replacement? I really don't want to visit the stealership because I know I'll have to buy some entire kit for that little piece.

Thanks!

 

Hey all. I'd like to get in on this thread as well. I just posted about this same type of problem of my truck idling way down and then coming back up and one you guys told me about the brake booster. What about the PCV elbow. What does the pcv look like and where is it located. I'm not afraid to do the work myself I just don't know what to look for to check and see if the elbow you guys are talking about is what is causing the problem.

Thanks,

 

cwindham,

not sure what motor you have, this applies to a '99 5.4L

look for the pcv valve on your passenger side valve cover, it plugs into the valve cover very near the oil filler cap. to remove it, just pull on it. be careful not to pull on the vacuum hoses, they are probably delicate since they wear out and usually disentegrate. if you have a pcv line problem, usually elbows, you should find your passenger side valve cover has a buildup of oil and dirt. if the elbow or line is leaking it will blow out a mist of oil in that area and the dust and dirt builds up over the oil.

my truck did the idle game yours is doing, i also had two codes PO171 and PO174. I found two elbows that were cracked. i replaced them with a couple of short pieces of vacuum hose, same interior diameter as the elbows. the way I see it, there is no point in replacing the elbows with more elbows unless you can find some made of a harder compound.

anyway, the idle problem stopped and the codes went away after I disconnected the battery and the pcm reset.

i doubt you have a brake booster problem, but, i'm not an expert.

if you have a dirty valve cover (top side) you probably have a pcv leak there. without going outside and lifting the hood, i want to say there is one more elbow that runs back towards the fire wall to a line that drops down behind the engine. not sure though. let me know if you need to know for sure and i will look under the hood for the second elbow.

clintc
99' F-150 XLT Supercab

 

Spark plug boots make a good replacement for some of those 90 degree elbows.

Steve

 

Thanks Guy's this thread has helped me alot. I was getting the lean bank 1 and lean bank 2 codes(98 5.4), and a crappy Idle. First changed out the fuel filter (no change) can hear a vac leak.Took it to a local mechanic who is determined to take the intake off and replace all gaskets (5hrs labor). I did the starting fluid trick to find the leak, and after reading this post traced the lines from the pcv valve to the back of the intake. The connecting boot fell apart in my hand (what a pos). Anyway just a thanks to you guys. I'm hopeful that this just went from a $400 reccomended fix to a $4 right fix.

Any other trouble spots (boots-connectors) I should look for while I'm in there????

 

i have a 97 4.6v8 w/183k miles on it, and i just recently changed my air filter this past weekend without changing it for awhile, and im curious since it is not getting more air from the new filter is that may be the cause of the lean condition?

p.s. i had the air filter changed by someone else while i was getting the oil changed, and to my knowledge, it was not an oil-filled filter, but the old one was dirty, so some of the junk may have gotten in there...

 

MSCRUTON - Did you ever figure out what is causing the stalling? I have the exact same problem on my 04 and cannot figure it out. Any help would be greatly appreciated.

 

hey i just fixed my f-150 4.6 CODES WERE PO174-PO171 IT WAS the elbow on the top of the intake on the back of the motor. thanks to all you ford lovers for the info.

 

Yea - It's a PITA to find - best way is just to follow the PVC line back / it ends at the elbow. There usually stuck on the manifold stem which makes it more fun to change, but it can be done with a little persuasion ..