The check engine light is on. A friend has the tool to read the codes and said the system is lean. I'v replaced the fuel filter, fuel pump, plugs, & wires. He also puled the PCV valve and cleaned it but he said it seemed fine. When he checked the code it said to look for a vac. leak. I looked at all the stuff I thought was a vac. line and they seemed fine. Is there some kind of trick to finding leaks? Any sujestions what to look for now?

 

You can try cleaning the MAF sensor: https://www.ford-trucks.com/forums/1...-cleaning.html

 

Last night with the truck running I went around the intake manifold, air box, the duct running from the air box to TB, and any vac. connections I could see giving quick blasts of ether. The RPM never jumped up. I'm going to get the T20 safty bit tonight so I can remove the MAF and clean it. There is another "plug" in the intake duct between the MAF and the TB any one know what that is and if it could cause this problem? Also I am guessing there is some mechanical part that the MAF controls to regulate the air coming in like a butter fly type thing? Could this be stuck open?
The truck has 124,000 miles. It may be a little slugish on take off but I've always thought it was under powered so its hard for me to say. I have a week and a half to get it e-checked so I can get my new sticker. Does unhooking the neg. battery cable really clear the CPU or does it only shut off the light on the dash? I was told that the light will go out until the error is found again but the codes will still be in the CPU for the EPA guy to see when I get it checked.

Also could one of these fuel system cleaners help?

 

Are you referring to the IAC (Idle Air Control), as being the other thing with a electrical plug???? It's located downstream from the MAF sensor.

 

IDK what its called. It's between the MAF and the T/B in the intake duct (the tube running from the air box).
What does it do? Could it cause the lean code?

 

Sounds like your referring to the IAC valve. It does as it's title suggests, by being conrolled by the computer, to bleed extra air into the intake, after the MAF sensor, to control idle speed.

It isn't likely to be the cause of a lean code imo, just idle speed problems.

Might be helpful if you would post ALL the trouble code NUMBERS, your friend pulled with his scanner.

The 4 bangers PCV hose seems to be a common vacuum leak area, so I'd check it out real good. Vacuum hoses, like the vapor recovery system, brake booster & even the HiVac system are also good suspects, so if your having any operational trouble symptoms with any of those systems, pay special attention to their vacuum lines & connections.

As Rockledge suggested, a dirty MAF sensor can cause a lean code, so if you've modified the air intake, or are using a over oiled foam,or cotton gauze air filter, or have any problems with the air filter fit, or air box not buttoned up properly, or fastners missing, or cracks or splits in the air box, that could let dirt get to the MAF sensor, as it could cause the MAF's heated elements to go out of calibration, confuse the computer & mess with the air/fuel ratio.

Dirty fuel injectors, low fuel pressure, clogged fuel filter, sluggish O2 sensor, ect,ect, the list goes on & on.

Lots of possibilities, so maybe listing ALL the trouble codes could help narrow the list down some.

 

I'll back up.
In Jan. "08 I took it to my friend to get tires. The check engine light had been on for a long time. 6 months or more but the truck seemed to run fine.

He went ahead and hooked up his scanner or what ever it is called it came back with 2 errors. I don’t know what the #’s were. 1 was a miss on cylinder 2 and 1 was this lean condition in bank 1.
He told me to replace the plugs and wires, new fuel filter. I did all that and a new air filter and changed the oil. I took it back so he could use the scanner tool to clear the codes. After he did about 20 to 25 miles the light comes back. So back I go and now he only gets the code about the lean condition.

So as I said last night I went all around the engine compartment with a can of ether trying to find a vacuum leak. I tried to use short bursts of the stuff but by the time I stopped I had a cloud floating around the compartment. I’m not sure how I did not blow my self up!
But I never got anything to raise the RPMs. Finally I pulled a vac. Line off the plenum and shot some in it just to make sure I would notice the effects of the ether when at idle. I did!

As of right now the truck is sitting with the negative battery cable removed to hopefully erase all error codes. I had been led to believe that all this would do is make the light go out but after reading on here I am thinking that this will indeed “clear” the codes.
I also intend to stop on my way home and get a T20 safety bit and a can of brake parts cleaner for the MAF.

I'm told that if the issue was along the lines of bad or dirty injectors or bad or low fuel psi. the truck should run poor. I can't really say the truck runs any different than it ever has. It does seem a little underpowred but I'v allways felt that.

Thanks

 

How many miles for the truck to do all of its “tests” that make the light come on?

I got a can of cleaner that says its for the MAF and T/B. Sprayed the living S#!T out of it. The MAF its self did not look dirty to me but when I sprayed it in the air box side of the T/B the stuff that pored back out looked like black coffee or something. Anyway I had the battery off during all this. Put everything back together after it dried and it started and ran fine. It was only about 12 miles to work this morning so I don’t know if that was long enough for all of the test to be done but so far no light.