Okay, second round for this thread. 98 4.6L, 4X4. Flowmasters, K&N filter. The truck idles real smooth, runs like a scalded ape and sounds wonderful. However, everytime the wife drives, the CEL comes on. I have driven with her and I can't figure out what she's doing to my baby.

So far, I've cleaned the MAF, throttle body, and last night while removing the EGR, I lost the socket off my ratchet in the depths of the intake manifold (not inside it, just somewhere between it and the block) which I can't find with my magnet.

All these things have certainly helped performance, but it still keeps throwing a code 401. I know it is an EGR code and I'll give the EGR another shot, but is there anyway it might be something else since it runs well.

My neighbor mentioned a fuel filter. Thoughts?

Not letting her drive is not an option, we just bought her an 03 50th AE vette and I'm not going to lose my privileges.

 

FordOkie,

Went back and found the other thread on this.

Saw a few suggestions, but the only thing I read that you checked were the vac hoses ( above the items above ).

Did you :
1. Check / clean / replace the DPFE ?

2. Check / clean / replace the EGR itself ( not usually this, but it has been from memeber reports ). A good thread by JMC on this :
https://www.f150online.com/forums/sh...hreadid=108512

3. Clean the EGR ports ( seems to be common on high millage 4.6L engines, but usually associated with pinging ).A thread on cleaning EGR ports
https://www.f150online.com/forums/sh...threadid=95863

Doing a search on the term P040* will provide 49 threads on this topic, so you can see them all, but these are the ones that I recalled were suspect on the 4.6, and checked real quick with the search.

If you can let us know what else you did ( dropping the socket was this checking or cleaning the EGR ) to check things it would help.
If there is a lack of pinging under load, I would guess it to be the DPFE, but that is a SWAG right at the moment, please provide some more info before you go out and buy one.
Steve

 

SSCULLY,
Thanks for the info. There was some pinging before I cleaned the MAF, but now there is none.

Dropped the socket while removing the EGR for cleaning. Still haven't gotten the socket yet.

I haven't cleaned the DPFE. I didn't think you could. Should I use contact cleaner or simply air? I saw this as a possible cause on another thread, but I thought it was usually throwing a 402, too much airflow code.

One thing I noticed during all of this is that there is a hose that runs from the valve cover to the air intake tubing just before it attaches to the throttle body. This appears to have some oil in it and the hose seems loose/worn, not a tight seal. Could this be a cause?

Thanks for the help.

 

This may sound funny but check the gas cap itself I had the exact same problem about 2 years ago truck ran great CEL kept coming on I kept clearing it finally took it to a buddy with a shop turns out the gas cap had a bad rubber gasket on it casueing the emission related componet to trigger the CEL. THE GAS CAP CAN ACTUALLY BE TESTED TO SEE IF IT SEALS PROPERLY. If the seal looks like it has rolled go buy a new gas cap. I realize this sounds crazy but you really should check it.

Richard D.

WHILE YOUR HERE CHECK OUT MY GALLERY:
https://www.f150online.com/galleries....cfm?gnum=2479

 

i think you should ride with your wife and find out what the heck shes doin. Maybe she uses the air con and you dont and its making something happen. Or maybe . . . . well it could be anything.

 

I have heard (not experienced myself) that a check engine light can be thrown if a vehicle is running while filling with fuel?

 

FordOkie,

I have been told soap and water with an old tooth brush is the way to clean it.
Same as cleaning the T/B and the IAC.

So you have cleaned the EGR, and it tested ok ( apply vac to it test in thread listing on P040* ).

The DPFE has gone both ways from posts that I have read. Never had it happen myself.

If you have a VAC line that is not fitting correctly, then yes this can be the cause of it. Easy to check, get some VAC line from Napa or the likes and replace it, clear the code and see if it comes back. I woudl think that if the wife is letting the truck shift short, that maybe there is a VAC line that is partial blocked, or the EGR ports are partially blocked.

So with a cleaned and tested good EGR, the next step would be check the EGR ports. This is a labor only project, no parts needed.

At least that is my take on it.

 

Thanks again for the input.

Today is the first day that she has driven it since I cleaned the Throttle body, EGR, and lost my socket. I'll post again to let you know how it went.

I have to say, it sure was running well yesterday after all that cleaning.