Hello all,
I am also new here and hoping I can get some info. I have a 1999 F-150 V-6 4.2 ltr with about 115,000 miles on it. This past summer the truck started to idle a little rough when parked and in gear. I took it in to a mechanic to get it checked out. He put some fuel injector cleaner in the gas tank and changed the fuel filter. Nothing. Lately it has gotten worse to the point of the CEL light coming on. The code is P3401 which the guy at Autozone related to a dirty or failed EGR valve. I bought one and changed it that night even though I knew it wasn't going to be that simple. I bought a coil pack at the same time figuring that with the mileasge I have on the truck that it was time to change it. I haven't installed the coil pack yet. I changed the plugs and wires last summer (2005). I don't remember what brands I used. I also changed a 3/8ths inch vacum line today that was looking pretty shabby. It runs like it has a vacum leak but I haven't been able to find one. I have read a thread on here about cleaning the MAF and I will give that a shot also. The truck seems to run better when it is cold and on first startup. It doesn't take long to get shakey again. I have never had to had any engine work done on this truck except for the mechanic changing the fuel filter and dumping injector cleaner in the tank. Any help would be appreciated.

Thanks,
Dan

 

Have you checked the PCV valve? Does it sound like an injector? If yes, then I would replace it.

Another thought. Obtain some O2 sensor safe throttle body cleaner. Clean out your throttle body then while the engine is running, shoot some through your brake booster vacum hose and one of the hoses in the intake hose (one of the two has vacum). see if that helps.

If not, perform a search on IAC valve.

 

Thanks Saint.
I have the throttle body off now. I have cleaned it up but it wasn't as bad I as thought (or was hoping ). I sprayed some card cleaner in the intake manifold but again, not as gunked up as I thought. I took The IAC valve off also and have cleaned that. I also checked the DPFE lines and sprayed some cleaner in those for good measures. I am going to put it all back together now and will report back later.

 

The only way to clean the TB is with a good set of pipe cleaners - make sure you get the EGR port real good. IMPORTANT: The IAC once cleaned w/seafoam you can move freely, you must hit it good w/WD40 and hand work it some more. If you don't have compressed air don't even attempt to clean your TB.
It will purr like a kitten if done properly - make sure to use high heat black RTV Permatex along with or without a gasket.

 

Thanks jbrew,

I put everything back together last night and the truck ran worse today. I didnt see any EGR ports on my TB. I didnt use pipe cleaners but I had it shiny clean when I put it back in. I haven't had any cold idle issues but I cleaned the IAC since I was in tear-down mode. I was going to try and work the IAC a little but didn't see how I could so I just hit it a lot with Deep Creep as best I could. I might have a look at it again tonight. I was going to pull a couple plugs to see what they look like. I might as well change the coil pack tonight also since I bought a new one. Do you think I need to pull the intake manifold to clean in there? I did that on my 98 Windstar. All but 2 of the EGR ports were clogged. After cleaning them, the vans runs like new.
What about the DPFE? Could that be the culprit? I had a bad one on my Windstar.
I wish I would have started all this when it was warm. My truck doesnt fit in my garage and the weather here is crap. Go figure.

Oh, and I also cleaned the MAF sensor last night.

 

You can use my barn - everybody else does !!! it's heated!! Guess I shouldn't say that lol. Holy Crap!! 98 Windstar , that brings back memories, I replaced a motor in one of those last year for an X-girlfriend - Had to lift the freakin Van up and off the motor that was fun...The DPFE is just a sensor and yes those are known to go bad - just test it. Deep creeps good stuff. Don't pull the manifold unless you need gaskets. At this point I would get the can of Seafoam you can suck threw the brake booster hose until your motor starts to crap out - shut it off let that Seafoam do it's thing for about 30 minutes to an hour. Fire her back up rev her up a few times , rest, rev her up some more until you don't see any smoke coming from the exhaust .

That should do yuh..

Good Luck

 

I did the seafoam injection before I started ripping everything apart. I didnt suck through the brake booster line but from a vacum connection on the other side of the engine. I am thinking of hitting it from the brake booster side. I am wondering if I dislodged some carbon while cleaning last night and it is lodged somewhere it shouldn't be.
A heated barn, some tunes, and a couple beers whould be perfect. I have the tunes on and the beer but it is hard to enjoys when you are shakin for the cold.

 

Why RTV black? Mine is orange....It says high temp silicone.

 

Orange will work - Black sets up quicker.

Yup , since my first heated garage - can't be without , 200amp phase 2 for the Ingersol Comp. Fridge , micro, cable, this computer.. I just need a lift and to get my brothers junk out of there and I'll be set.

There's a measly beer toll you have to donate to , but it's worth it.

 

Sounds like the perfect setup. My computer is in the garage which is usually heated for the most part. To make a long story short, I built this computer right before Christmas a couple years ago. Since the tree was standing where I was going to put the computer, I kept in the garage. Since the garage is too damn small for any of the vehicles I own (the Windstar barely fits at an angle), I got some carpet scraps from a job I was on at the time, a table from Sam's, a mini fridge they were going to throw away at work and bingo, my little corner of the house. I have a TV up in the corner from where I am sitting for watching "da Bears" and a crappy old radio that plays classic rock all night long. But I digress,

The Seafoam is soaking and I installed my new coil pack and am dressing up the spark plug wires to kill time.

 

Hmmm, well so far no improvement. The Seafoam is still burning off though. I am not sure what to check next.

 

Now that you done all that cleaning and inspection, how about re-visiting what the code 3401 really means.
It's cylinder 1 intake air control circuit open condition or related fault.
Might have something to do with idle quality.
People have to learn to use Ford specific code charts, not something said from Auto Zone or other sources unless they are known to be correct.
Let us know what you find.

 

Holy crap, the guys asking for help not a lecture.

 

Good Luck Dan

 

Maybe Blue will climb down from his pedistal and give yuh hand.