[QUOTE=alloro;13847362]Take another reading of the fuel pressure. You wouldn't be the first person to get a bad pump.[/

Fuel pressure is at about 38psi

 

Yes, Im only this far through the thread...and I promise if you lived here you would be reading it too.

 

I have had the engine lights on my Expy for the last year. After replacing all of the above mentioned items they told me I had to replace the entire muffler system. 1800 was a rough estimate of what the said someone else paid not that long ago. Going under the hood tomorrow and looking for this little part and replacing.

 

I just had the po171 come up and it was the wire that goes to the maf had come out of the tube so there was a large leak after the maf sensor. just pushed it back in and cleared the code.

 

Check engine light with the "system too lean bank 1, system too lean bank 2" codes the other day. I got these a couple of years ago. It was the vacuum line elbow at the rear of the passenger side head. Since then, I changed out all the vacuum line I could find. This time it was the intake tube going into the throttle body. Last time I had it off, I must have kinked it putting it back on. Luckily I found one at a local u-pull junkyard for $5.

 

That looks like heat damage to me. Was that damaged section anywhere near the exhaust manifold or EGR tube?

 

No it wasn't near any heat source. When I found it, it was folded over underneath at the 6 o'clock position. I unfolded it and it started to break apart. I put it back on, duct taped it, then put the clamp back on. It looks worse in the pic because I peeled off the duct tape and took some little pieces of the hose with it.

 

I seem to have the same symptoms many of you have experienced... Weird/rough idle at times, loss of power!!! I have limited mechanical experience but based on what I have read doing searches, if this is the problem even I should be able to fix this. Only question is most hear seam to have the 5.4L does this apply to my 4.6L (windsor) 4x4 156,000m? I should mention I have not seen a CEL to date but we did just buy this a month ago... Today I will be cleaning the MAS, replacing the PCV Valve and the Air Filter?

 

I had a PO171 error on a 99 Expedition 5.4. The issue turned out to be a loose hose in the throttle body. I pushed it back in, cleared the code, and have had no problems since.



99 Expedition 5.4 loose hose in throttle body causing PO171 error

 

I wanted to be sure to post the solution... I know it's been YEARS since I posted my problem, so I copied it here. Same as most in the thread. None of my tubes were at all damaged; after replacing a clogged fuel filter and not getting anywhere with even that, I finally sprang for a low-cost RockAuto MAF and it has been smooth (and much more powerful) sailing ever since. So, sometimes it is the MAF. Too bad you have to pretty much do elimination on everything else first.

 

That's good to know. My code has come back as well. Can't even tell you when, that's how long it has been. I do need to love her more. Plus I have been driving her way less then usual, almost seats for a couple of weeks; before I drive her again. I have so many man hours on her don't see any reason to not fix her. Will keep everyone posted.

 

I have a 1999 F250 5.4 . What should fuel rail pressure be? Had a gauge on it today driving around. With engine(and fuel pump) cold, no problems and about 30 psi. The longer I ran it, the pressure dropped to 22psi and truck ran like crap. Bad fuel pump?

 

This is the navigator/expedition forum, you want to go to this forum for the F-series trucks: 1997 - 2003 F150 - Ford Truck Enthusiasts Forums

 

Whelp I just seafoamed the heck out of her. She was thirsty. She end up drinking about half if not a little more then I expected. Added about half the can in a quarter tank. Ran her down 495 at 70-75 with overdrive off. She acted as if she was going to stall when I was adding the foam but didn't. Anyway, the only smoke I saw was when I pulled off my block. I've seen more smoke from a weed whacker on startup.

I will add she does idle a heck of a lot better. I can barely hear her. Should I clear the codes? I will have to remove the battery, no code scanner yet. Saving up for a good one.

Update: so far so good. Cleared the code and filled the tank with 91(not trying to start another debate about fuel). It is just what I like; the feel and driveability is better. Plus, she is less funky in smell.

 

You don't always get a big puff of smoke, sometimes it's more subtle.