ok heres the deal i had the dreaded p0401 insufficient egr flow. well after all kinds of headaches i finally found that the ports or whatever in the neck of the throttle body were clogged. after i cleaned them out it ran great and was fine for about 4 - 6 months. then the light came on again and it started running alittle different so i took the throttle body back apart and it was clean so i figured out that it was the egr positioning sensor which i had replaced before i found the clogged ports so i changed it again and the truck was fine for about 4-6 months. then the same thing the light came on and it started running weird again. so long story short this has happened 4 times now and my light just came on again tonight and it started running the same way again i checked the code and its the same one. so PLEASE HELP cause when i change it it works for a couple of months and the same thing over again whats causeing this. i have a 99 f150 4x4 4.6 auto only mods i have are a k and n fipk and the superchips power programmer and a 3" exhaust with and imco extreme muffler just single 3" from the y back. so if anyone has any suggestion as to why this keep repeating and last the same amount of time all the time please let me know.
thanks
jesse

 

????????????

 

Idunno - sounds like it's possessed.

 

Two questions, where is this EGR position sensor you changed?
And did this start after you put the big muffler on?

 

Jesse,

Take a look at the other two active EGR threads and look for the schematic of the EGR circuit and read the responses. Lots of good info in there as to possibilities. Everything from chunks-O-stuff floating around and blocking flow to cracked vacuum lines. May be time to break out the vacuum pump and gauge.

 

Well, I don't really need to look at anything because I ask him about the EGR position sensor.
THERE is none on a 4.6L engine. These have not been used since the 5.0 and 5.8L push rod engines.
I also have a reason for asking about the exhaust.
I'ts not at all that I really need to know about these parts.
Thanks for your concern.
He needs to know about all this.

 

Hey Blue , are you out there by Hummelstown, harrisburg area?

 

No. Look up in my location info at the top right.
Easton, Beth. Allentown, Lehigh Valley. Right across the river from N.J.

 

My Bad, Blue... I looked back on my post and I must've pushed the quote button instead of the reply buttom :o

I guess that's why they created the preview buttton and this is one time I neglected to use it! Please accept my most humble applogy! I have learned quite a bit from your various postings!

 

I'm cool. Thanks.
I think he is really meaning the EVR and not a position sensor.
For the exhaust, there is a remote possibility that the exhaust is not building enough pressure in the EGR tube for the DPFE to measure hence the 402 code.
Being behind a key board and doing interpetation based on what is reported is alway tough and risky. Too many eyes have other opinions.
I have to think about how the systems work then all the ways something could affect them or there's no benifit in trying to help.
Much of the last 35 years have been spent interpeting machine trouble printed outputs , breaking down the binary, octal and hex code words (number strings) to id what the problem was and the hardware involved, then taking equipment out of service for the repair.
I don't know any other way to relate but the tech of it and circuit disriptions of operation.
My living depended on it.
Good luck.

 

Until last year I ran the pike down that way about a dozen times a year to a little town -Hummelstown. Allentown wasn't far from , went through the three tunnels - Liked that run PA's nice , allot of construction on the pike tho, other than that it was a nice ride.

 

the little plastic rectangle with the two vaccum hoses and the plug of wires in it. no the exhaust was put on inbetween all this happeninh i think. i just called it a positionig sensor cause thats what they call it at auto zone and ive had to get so many its burned into my head. and i did read all the other egr threads. but i was hoping someone would have a suggestion about why its a repeat.