Hey all I got a 1999 ford expedition yesterday and today I got a check engine light. The codes were P0171 and P0174 for fuel trim bank one and two condition and P0401 for EGR system fault (exhaust gas recirculation). It seems to run really well and idled for two hours with the ac on at DMV (the check engine light was already on at this point). The original owner said he has the battery out to charge it. But now I wonder if it was to hide the codes. I need to drive cross country Can I fix these sensors after my trip? Am I screwed? Thanks in advance!
Bought yesterday threw codes today!
- Thread starter Tacsat117
- Start date
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FordandPolaris
Full Access Members
Agreed, the codes are not catastrophic and you should be fine going across country. You may get some rough idle if on the highway for long periods, but otherwise it will survive. its most likely the fitting leading from the PCV valve to the very back of the throttle body. Cost me 30 bucks to fix, here is a link to a thread all about the issue...
http://www.expeditionforum.com/f27/rough-idle-p0171-p0174-heres-what-you-need-check-first-4926/
http://www.expeditionforum.com/f27/rough-idle-p0171-p0174-heres-what-you-need-check-first-4926/
Thanks for getting back to me so quick! Forums rock! I've been driving it around Albuquerque and plan on taking it on little highway trips (30 miles or so) just to make sure it's good to go. Seems like a good truck. If all goes well ill be sitting y a mountain camp fire in fours years thinking about what a good deal Bessie was!
Yea mine had these codes when I first bought it. Like said the culprit was the elbow behind the throttle body. I bought 2 hoses from Ford and the rough idle went away and got better MPG.
You can drive it forever with those codes and have no major drivability issues.
You can drive it forever with those codes and have no major drivability issues.
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Thanks to your advise I took my trip and the truck did fine. I'm starting to think that my problem might be computer based. I noticed that after a reset. Every thing works great for awhile then things seem to degrade. The check engine light comes back on, the four wheel drive won't shift into four wheel drive, and my odometer goes out. I could be imaging this. It I seem to have less dash icons on start up after the check engine light comes on. When I get settled I'll reset and take notes.
The first gens had a bad solder on the cluster, especially for the odometer I really wouldnt worry about it.
FordandPolaris
Full Access Members
Start with the PCV valve. If it is the original PCV in there, its pretty much a guarantee that it is causing a vacuum leak. 4WD could be the shift motor on the tcase too.
johnjon
Member
as far as the egr code i had the same code but to make a long story short check and clean the passages that lead from the egr valve tp the throttle body. this might save u some headaches
shadow460
Full Access Members
I've dealt with vacuum leaks twice. The first was my 98 F-150 with leaks in several vacuum lines and in one of the intake gaskets. The second was in my wife's older F-150. ONe of the vacuum lines in the EGR control system sprang a leak and it threw blinky codes for the EGR valve not opening and closing (33), and for a lean mixture at the O2 sensor (41, I think).
I ran my '98 F-150 for six years with the check engine light on from those codes. It finally burnt out! I fixed one of the leaks and changed the PCV valve, then let my mechanic find and fix the rest. My wife's truck ran okayish for several weeks with the vacuum leak it had until we got it fixed.
I ran my '98 F-150 for six years with the check engine light on from those codes. It finally burnt out! I fixed one of the leaks and changed the PCV valve, then let my mechanic find and fix the rest. My wife's truck ran okayish for several weeks with the vacuum leak it had until we got it fixed.
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