P0171 1997 Ford Expedition

[Eugenia Bermudez]

It's in the shop now having the fuel pump replaced. I love my Ford Expedition 4wd it's all I ever wanted in a vehicle, I don't mind that it is a v8 and burns more gas than a smaller vehicle. I love fishing and it will take me where I want to go.

 

[Tbaker]

I too chased a P0171 code for a number of months and mine turned out to be cracks in a tiny L shaped hose that connects the back of the motor to the PCV valve. With that said it's not an easy part to replace by any means and my first one dropped into the top of the block. The next one I tied to a string and could never get it to push onto the fitting. Both were purchased at FORD. I then got an aftermarket one at an O'Reillys and that went on in a matter of seconds. You definitely want to lube both ends or you'll never get them on as you can only use your left hand and you just don't get adequate leverage to push on the hose to the fitting. Once installed I cleared my codes and have driven hundreds of miles with no returning of the check engine light. I too messed with my mass airflow sensor for some time before reading a thread on a blog what fixed someone else's problem. Good Luck

 

[Eugenia Bermudez]

The fuel pump was replaced. Drove fine first few miles then it started losing power again. I drove it home and put in park and let it idle. I happened to turn on the heater and that really made it bog down. Went through each setting on the heater and AC and it seemed like each setting sucked the power out and it sounded like crap. I'm afraid to drive it now cause I don't want to cause any damage.

 

[Eugenia Bermudez]

This is what has been replaced and each time something was replaced it drove a little better then it started losing power again and hundreds of dollars no a couple thousand dollars later and I'm at wit's end.
MAF, purge valve, purge solenoid, PCV valve. Codes were cleared. Took it to another shop because it was losing power and they smoke tested it and the EGR valve needed replaced. Replaced EGR check engine light came on p0171 code. They tested fuel pressure and replaced fuel pump. And now it's worse.

 

[Eugenia Bermudez]

I just want add that when my 1997 Ford Expedition had first had the check engine light on and codes, I called my local Ford dealership here in Eureka, CA and spoke to the technition about the check engine light and codes wanting to make an appointment for diagnostics and repair he told me he couldn't do a diagnostics on my vehicle because it was over 20 years old and he wouldn't be able to get parts for it. That's why I've been taking it to other shops that just seem to be throwing parts at it. If I can get parts, and the other mechanic shops can get parts why can't Ford dealership and repair shop get their own parts???

 

[Trainmaster]

A Ford dealer can get parts. They just don't want to be bothered because they either don't have diagnostic skill or feel you won't spend the money to fix things right.

Seems like you have a vacuum leak. That's why the heater was causing it to bog down. A proper diagnostic test has to be done with a smoke generator. Seems like up to now the people working on this truck have just thrown unnecessary parts at it.

As has been said here many times, the EGR hoses break down at this age and are a huge source of leaks. They are cheap, so nobody makes money replacing them. Easier to sell you a fuel pump.

 

[Hamfisted]

Hey Hamfisted, I am chasing a low power issue in my 5.4 2v, I have 30 PSI at idle and with the FPR vacuum pulled it goes to 40 PSI, should my gauge be higher when I rev?

Well, 28-45 psi is the specs. Have you put a new fuel filter in it ? 40 psi at idle is normal, so you're kinda on the low end. But I don't know if that would cause your low power issue unless under load it's just not flowing enough volume. Getting any DTC codes ? Air filter clean ?

 

[Tommie]

Well, 28-45 psi is the specs. Have you put a new fuel filter in it ? 40 psi at idle is normal, so you're kinda on the low end. But I don't know if that would cause your low power issue unless under load it's just not flowing enough volume. Getting any DTC codes ? Air filter clean ?

Yeah new fuel filter and air filter, going to smoke test it and see, my PVC hose and valve are new, I think I know what it is unfortunately, very very minor head gasket leak, about to do a round of blue devil and see if that does the trick and pending smoke test will fix any leaks and if still acting up will do a compression check. Also going to do a deep clean on the TB and EGR system. Truck runs much better with the new Cat tho. Previous owner sucked at maintenance sadly. Truck has 240,000 miles so fuel pump is on the list of items to take care of also. thanks for the reply.

 

[Tommie]

I just want add that when my 1997 Ford Expedition had first had the check engine light on and codes, I called my local Ford dealership here in Eureka, CA and spoke to the technition about the check engine light and codes wanting to make an appointment for diagnostics and repair he told me he couldn't do a diagnostics on my vehicle because it was over 20 years old and he wouldn't be able to get parts for it. That's why I've been taking it to other shops that just seem to be throwing parts at it. If I can get parts, and the other mechanic shops can get parts why can't Ford dealership and repair shop get their own parts???

Eugenia I def second replacing your PCV valve and more importantly the hose. Rockauto has both at a good price or amazon has them with prime shipping if you're a member. Simple job TBH, any shady tree mechanic can replace within an hour and less than $40 to do.

I'd also do a smoke test and make sure you don't have other leaks, the AC being on and making it run worse just proves that its likely a vacuum leak somewhere and the PCV is a huge culprit. Do you see any oil or water leaking around the passenger side spark plugs? Your intake manifold gaskets probably need changed as well and the water or oil can ground out the cylinder that's affected.

 

[Hamfisted]

Yeah new fuel filter and air filter, going to smoke test it and see, my PVC hose and valve are new, I think I know what it is unfortunately, very very minor head gasket leak, about to do a round of blue devil and see if that does the trick and pending smoke test will fix any leaks and if still acting up will do a compression check. Also going to do a deep clean on the TB and EGR system. Truck runs much better with the new Cat tho. Previous owner sucked at maintenance sadly. Truck has 240,000 miles so fuel pump is on the list of items to take care of also. thanks for the reply.

Yeah, I just replaced my head gaskets at 220k . Had them rebuilt while it was apart. Wasn't losing power, just a build up of pressure in the coolant reservoir and started seeing soot in the coolant. Now that everything's back together and running right I only see about 3-4 lbs of pressure in the reservoir. Cleaned the intake runners with Marvel Mystery oil and rags, they were carboned up, same as the intake ports. The machine shop cleaned up the heads and installed new springs and seals. I installed new rocker arms as well during reassembly.