Codes 171 and 174
Thread Starter
|
New User
Joined: Jan 2008
Posts: 5
Likes: 0
Codes 171 and 174
I have an 01, F-150 with a 4.2 liter. I get codes 171 and 174 every couple days. I have checked till I'm blue in the face for an external vacuum leak. I have replaced the PCV and checked all my vacuum lines. I replaced the fuel filter(IT WAS BAD). I have had the truck about 6 months and other than this, which my gas mileage has went way down, I love it. Is there a definite way to diagnose the MAF, which I have cleaned with aerosol MAF cleaner? Am I down to intake gaskets being my last hope?????? Any suggestions greatly appreciated...Thanks
Posting Guru
Joined: Oct 2005
Posts: 2,209
Likes: 1
From: Louisville, Kentucky
Hello Bassmaster1227 and welcome to FTE! 
From my service manual CD.
Fuel System DTC Reference List:
-- Bank 1 = DTCs P0171 (lean) and P0172 (rich)
-- Bank 2 = DTCs P0174 (lean) and P0175 (rich)
From my service manual CD.
Fuel System DTC Reference List:
-- Bank 1 = DTCs P0171 (lean) and P0172 (rich)
-- Bank 2 = DTCs P0174 (lean) and P0175 (rich)
- Check intake air system for leaks, obstructions and damage.
- Check air cleaner element, air cleaner housing for blockage.
- Verify integrity of the PCV system.
- Check fuel delivery system and filter for restriction.
- Check for vacuum leaks.
Thread Starter
|
New User
Joined: Jan 2008
Posts: 5
Likes: 0
Thanks KingRanchMan
Yeah I forgot I had already put a new air filter in it, checked all the duct work, because the first couple times it happened it had been rainy days and I thought I may be getin moisture in my air intake system. I'll try the propane, I've went through plenty of carb cleaner lookin for an intake leak and had no luck....I'll try the propane though and thanks again!!!!! Bassmaster1227
Yeah I forgot I had already put a new air filter in it, checked all the duct work, because the first couple times it happened it had been rainy days and I thought I may be getin moisture in my air intake system. I'll try the propane, I've went through plenty of carb cleaner lookin for an intake leak and had no luck....I'll try the propane though and thanks again!!!!! Bassmaster1227
Hotshot
Joined: Jul 2005
Posts: 11,931
Likes: 180
my 5.4 motor has two vacuum hoses on the drivers side center that are about 8 inches long and go from the exhaust manifold tubing area up to the EGR valve. looked o.k., but i pulled both hoses off and one was cracked and hard from the heat in this area. i think they were 1/4 inch ID., about 8 inches long.
Thread Starter
|
New User
Joined: Jan 2008
Posts: 5
Likes: 0
I went around everything with propane and got nuthin. Every vaccum line except the small plastic lines I put hose clamps on, cleared my codes, it made it almost 2 whole days this tiime before the check engine light came back on???
Posting Guru
Joined: Oct 2005
Posts: 2,209
Likes: 1
From: Louisville, Kentucky
You are getting codes for both banks lean. The PCM therefore has reached its limits of adjusting the fuel tables on the rich side. What modifications or changes from original equipment intake system and air cleaner have been done to your truck?
Thread Starter
|
New User
Joined: Jan 2008
Posts: 5
Likes: 0
I have no air/exhaust/performance mods. The whole truck is completely stock. It has a leveling kit on the front end other than that it doesn't have anything done to it. I'll be glad when I get this figured out though the 5 to 7 MPG less is drivin me crazy....I still appreciate any help.....
Trending Topics
Posting Guru
Joined: Oct 2005
Posts: 2,209
Likes: 1
From: Louisville, Kentucky
What I was getting to, if you have any leaks in the intake after the MAF, then that is unmetered air into the engine. That is why the first two bullets in the service manual mention the checking the intake and air cleaner thoroughly.
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
2027 Ford Super Duty Buyer's Guide (Every Model, Engine, & Package)
Brett Foote
Top 10 Ford Truck Tragedies
Joe Kucinski
AEV FXL Super Duty - the Super Duty Raptor Ford Doesn't Make
Brett Foote
Lobo Vs Lobo: Proof the F-150 Lobo Should Be Even Lower!
Michael S. Palmer
Ford's 2001 Explorer Sportsman Concept Looks For a New Home
Verdad Gallardo
10 Best Ford Truck Engines We Miss the Most!
Joe Kucinski
2026 Shelby F-150 Off-Road: Better Than a Raptor R?
Brett Foote
2027 Super Duty Carhartt Package First Look: 12 Things You NEED to Know!
Michael S. Palmer
10 Most Surprising 2026 Ford Truck Features!
Joe Kucinski
Senior User
Joined: May 2005
Posts: 305
Likes: 1
From: Omaha, NE
You need to replace the upper intake gaskets and bolts with these updated parts.<TABLE cellSpacing=0 cellPadding=3 border=1><TBODY><TR><TD class=NOBOTTOMBORDER align=left>1L3Z-9H486-AA</TD><TD class=NOBOTTOMBORDER align=left>Port Gasket</TD></TR><TR><TD class=NOBORDER align=left>3F2Z-9S479-AA</TD><TD class=NOBORDER align=left>Isolator Bolt</TD></TR></TBODY></TABLE>
New User
Joined: Aug 2007
Posts: 4
Likes: 0
po 174
bassmaster, I have a 150 w/5.4 and was getting the 174 code.
I exhausted alot of the same possibilities ,I went cheepest first I changed my fuel pressure regulator and that solved my problem . You could go that route
the diaphram in there may be bad.
I exhausted alot of the same possibilities ,I went cheepest first I changed my fuel pressure regulator and that solved my problem . You could go that route
the diaphram in there may be bad.
Thread
Thread Starter
Forum
Replies
Last Post
J H
Explorer, Sport Trac, Mountaineer & Aviator
6
Dec 7, 2008 07:12 PM
