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  #1  
Old 05-14-2012, 08:00 AM
stroh69 stroh69 is offline
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Default P0171 and P0174

I have a 2002 Ranger Edge with a 3.0L V6. I have the check engine light on and it's showing 171 and 174 codes (bank 1 lean and bank 2 lean). It wouldn't start one day (ran extremely rough then stalled out). Had it towed to a shop and they found the ignition coil burned up. Apparently ford has recognized that the lean codes can cause problems with the coil. Replaced the coil and couldn't find anything else wrong. Two weeks later had the exact same problem with the same two codes. Towed to the shop again and the mechanic found the PCV valve tube broken causing a vacuum leak. Ignition coil burnt up again ( replaced this time no charge). 50 miles later cel back on with same codes. My fuel pressure is 55-58 with the engine running. Should be 60-65. Is that low enough to cause a lean code? Replacing fuel filter to see if that is a problem. Also, I have checked all vacuum hoses for leaks and found none. Any advice would be appreciated.
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  #2  
Old 05-14-2012, 08:16 AM
modelageek modelageek is offline
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Default Re: P0171 and P0174

Quote:
Originally Posted by stroh69 View Post
I have a 2002 Ranger Edge with a 3.0L V6. I have the check engine light on and it's showing 171 and 174 codes (bank 1 lean and bank 2 lean). It wouldn't start one day (ran extremely rough then stalled out). Had it towed to a shop and they found the ignition coil burned up. Apparently ford has recognized that the lean codes can cause problems with the coil. Replaced the coil and couldn't find anything else wrong. Two weeks later had the exact same problem with the same two codes. Towed to the shop again and the mechanic found the PCV valve tube broken causing a vacuum leak. Ignition coil burnt up again ( replaced this time no charge). 50 miles later cel back on with same codes. My fuel pressure is 55-58 with the engine running. Should be 60-65. Is that low enough to cause a lean code? Replacing fuel filter to see if that is a problem. Also, I have checked all vacuum hoses for leaks and found none. Any advice would be appreciated.
fuel pressure seems fine......do you have the flex fuel?..........my guess is the MAF..try cleaning it with CRC.......also make sure the airfilter is good and the intake tube is clear.......

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also check codes periodically to see if you can catch a pending one.
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2004 Ext Cab, 4WD, 4.0, Auto, 154k. (4.0 engine is out of a 2009 Ranger w/96k) ( as of 7/1/2017)

2004 Ranger, Ext Cab, 2WD, 3.0, 5 speed , 4WABS, crank windows, no cruise, Edge 116k.(6/5,2014) (SOLD).
1999 Ford Ranger, Reg Cab, 2.5, 5 speed, 2WD, no AC, 150k (SOLD).
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  #3  
Old 05-14-2012, 08:53 AM
stroh69 stroh69 is offline
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Tried a new MAF already. Hope it's not that because I can't return it.

When I said the fuel press was between 55-58 the needle was fluttering extremely fast. After installing the new filter it is rock solid on 58 so I'm hoping that means the fuel pump is ok.

We reset the codes and we'll see if they come back. The air filter was just replaced also.

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Also it is the flex fuel.
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  #4  
Old 05-14-2012, 09:04 AM
modelageek modelageek is offline
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Default Re: P0171 and P0174

Quote:
Originally Posted by stroh69 View Post
Tried a new MAF already. Hope it's not that because I can't return it.

When I said the fuel press was between 55-58 the needle was fluttering extremely fast. After installing the new filter it is rock solid on 58 so I'm hoping that means the fuel pump is ok.

We reset the codes and we'll see if they come back. The air filter was just replaced also.

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Also it is the flex fuel.
just curious. how did you try a new MAF and at the same time hope it is not the MAF becasue you cant return it
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2004 Ext Cab, 4WD, 4.0, Auto, 154k. (4.0 engine is out of a 2009 Ranger w/96k) ( as of 7/1/2017)

2004 Ranger, Ext Cab, 2WD, 3.0, 5 speed , 4WABS, crank windows, no cruise, Edge 116k.(6/5,2014) (SOLD).
1999 Ford Ranger, Reg Cab, 2.5, 5 speed, 2WD, no AC, 150k (SOLD).
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  #5  
Old 05-14-2012, 09:38 AM
stroh69 stroh69 is offline
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As I stated in the first post I replaced the MAF but that was no help.

I hope I didn't get a bad one from the parts store because I can't take it back.

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My bad. I thought I put that in the first post but I didn't. Sorry for the confusion.
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  #6  
Old 05-14-2012, 11:23 AM
oregonhighgp oregonhighgp is offline
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Default Re: P0171 and P0174

hi there, I've had that same problem also p171 & p174 , 4.0 engines have a upper intake gasket (3 total) that leak air,they need to be replace. they're about 22.00 bucks for the set . I've replace them and my gas mileage improve finally,and no p171&p174 codes.
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Old 05-14-2012, 05:52 PM
stroh69 stroh69 is offline
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Upper intake manifold gasket/seals were replaced when The PCV valve and tube was replaced. The manifold had to come off to get the tube out.
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  #8  
Old 05-15-2012, 05:34 AM
Aladon Aladon is offline
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Default Re: P0171 and P0174

I'm having the same codes on my 2004 3.0
I spent about $900 last year replacing a bunch of stuff, and even had them to a fog test after everything was replaced and put back together (there was a bunch of regular maintenance stuff in there too) and there were no leaks. I just replaced my fuel filter about a week ago, and i still have the codes coming up.
**From what I've been able to find on the internet, it might be that one (or more) of the vacuum lines for the intake system could be worn out. There's an elbow line that many people have said was the problem.**
I think I found the elbow, but I'm not sure as I'm not all that knowledgeable when it comes to automotive. I'm more of a computer junky, honestly... lol
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  #9  
Old 05-15-2012, 11:07 AM
Fordzilla80 Fordzilla80 is offline
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Default Re: P0171 and P0174

Unfortunately, the quickest way to track this problem down is to hook the truck up to one of the pricey software programs and watch the fuel trims while the truck is running. With the computer hooked up, if there is a specific cylinder(s) running lean, It should show up on the data report.

If I remember correctly, there was a TSB on this exact issue back from 2005. I don't have any access to the info though, so maybe someone else who does can shine some light on the subject.
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  #10  
Old 05-15-2012, 11:38 AM
Aladon Aladon is offline
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Default Re: P0171 and P0174

First: I love the quote Zilla. Reminds me of my job. Every time we get something running smooth, a greater idiot appears to mess up what we fixed.
Second: What is THB? There are too many acronyms floating around the world today...
and lastly: What kind of software thingy you talking about? would an average autoshop have one? i spent almost $1,000 last year trying to get this light to go away (a lot of overdue maintenance stuff included), and it lasted for about 7-8 months, and then magically it's back....
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'04 Ranger Edge 3.0L-V6 RWD 4.10 gears - Automatic(5R55E)
Cat-back Flowmaster 2-chamber single to dual exhaust
K&N FIPK Cold Air Intake w/blue wrap
Underdog Underdrive Pulleys - Blue
Superchips Cortex Programmer
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  #11  
Old 05-15-2012, 12:04 PM
Aladon Aladon is offline
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Default Re: P0171 and P0174

Found a very technically inclined thread on these forums regarding this issue.
Adaptive Fuel DTCs Diagnostic Techniques (P0171/P0174)
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'04 Ranger Edge 3.0L-V6 RWD 4.10 gears - Automatic(5R55E)
Cat-back Flowmaster 2-chamber single to dual exhaust
K&N FIPK Cold Air Intake w/blue wrap
Underdog Underdrive Pulleys - Blue
Superchips Cortex Programmer
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  #12  
Old 05-15-2012, 01:58 PM
modelageek modelageek is offline
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Quote:
Originally Posted by Fordzilla80
Unfortunately, the quickest way to track this problem down is to hook the truck up to one of the pricey software programs and watch the fuel trims while the truck is running. With the computer hooked up, if there is a specific cylinder(s) running lean, It should show up on the data report.

If I remember correctly, there was a TSB on this exact issue back from 2005. I don't have any access to the info though, so maybe someone else who does can shine some light on the subject.
For what it's worth the free version of torque will read fuel trims, o2 volts, MAF!, etc

*you will need an android device and a Bluetooth obd interface ....I bought my elm327 of eBay from a guy from Brooklyn..I paid $14
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2004 Ext Cab, 4WD, 4.0, Auto, 154k. (4.0 engine is out of a 2009 Ranger w/96k) ( as of 7/1/2017)

2004 Ranger, Ext Cab, 2WD, 3.0, 5 speed , 4WABS, crank windows, no cruise, Edge 116k.(6/5,2014) (SOLD).
1999 Ford Ranger, Reg Cab, 2.5, 5 speed, 2WD, no AC, 150k (SOLD).

Last edited by modelageek; 05-15-2012 at 03:03 PM. Reason: *
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  #13  
Old 05-15-2012, 08:44 PM
Fordzilla80 Fordzilla80 is offline
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Default Re: P0171 and P0174

Quote:
Originally Posted by Aladon View Post
Found a very technically inclined thread on these forums regarding this issue.
Adaptive Fuel DTCs Diagnostic Techniques (P0171/P0174)
I don't have much time to read through all of what he posted at the moment, but it looks to reinforce what I was referring to.

TSB is a Technical Service Bulletin. They're guidelines released by a vehicle manufacturer and sent to dealer service departments worldwide. They basically tell the technicians how to troubleshoot and fix a common re-occurring problem.

For future reference, you see how TSB is underlined? If you see an acronym here on FRF that is underlined, you can simply hover over it with your cursor, and it will tell you what the acronym stands for. It's a pretty cool little feature they have here.

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Quote:
Originally Posted by Aladon View Post
First: I love the quote Zilla. Reminds me of my job. Every time we get something running smooth, a greater idiot appears to mess up what we fixed.
Second: What is THB? There are too many acronyms floating around the world today...
and lastly: What kind of software thingy you talking about? would an average autoshop have one? i spent almost $1,000 last year trying to get this light to go away (a lot of overdue maintenance stuff included), and it lasted for about 7-8 months, and then magically it's back....
Thanks, the quote sure is a truthful one.

The software will be available at any decently equipped automotive repair shops. Your local corner garage probably won't have it, but your dealer definitely should. What you should do is find a garage full of Ex-Ford mechanics. There's a place in my town that was started up by a group of Ex-Ford Diesel Specialists. It's like Super Duty heaven there, but they do service other vehicles as well. I took my Ranger to them one time when I was fighting an idle issue that wasn't throwing a code. They were able to monitor the fuel trims on the laptop, and he was able to see that the IAC valve was overworking itself. Sure enough, a new IAC fixed my idle issues.
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  #14  
Old 05-16-2012, 01:27 PM
gcextreme gcextreme is offline
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Default Re: P0171 and P0174

I had the same codes 2 months ago.

Check your vac lines.
And your spark plugs.

I had a disconnect vac line, it was the small line coming out of the big intake hose about 6" before the throttle body area.

Also clean the PCV valve thing.


So here's what i did and i haven't had any further issues.

Cleaned the MAF, it was dirty.
Cleaned the PCV.
Replaced all spark plugs.
Found that disconnected vac line, fixed it.
Replaced fuel filter.
Ran some seafoam in the gas.

Haven't had the cel since.
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  #15  
Old 05-16-2012, 03:18 PM
Aladon Aladon is offline
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Yeah, I had all that done last May, and around jan/feb started getting the codes again. Just haven't had the money to go get it looked at again. Of course, my inspection runs out this month, so I gotta get it fixed pdq. Lol.
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Cat-back Flowmaster 2-chamber single to dual exhaust
K&N FIPK Cold Air Intake w/blue wrap
Underdog Underdrive Pulleys - Blue
Superchips Cortex Programmer
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