99 4.0L problems
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99 4.0L problems
Hello everyone, im new here and have been looking at previous posts looking for help with my problem,but with the suggestions still can seem to have any luck, first off i have a 99 4x4 ranger, with a 4.0L and automatic transmission
im getting 3 engine codes
p0171
p0174
p1151
i have poor gas mileage, lack of power, rough idle, and almost seems after driving at a constant speed then letting off the gas to say get off an exit ramp, the engine will start jerking like it wants to die, maybe miss fire, then when you take off again it wants to jerk and buck, but straightens itself out and goes on, im at a loss, anything would be a help
thanks
im getting 3 engine codes
p0171
p0174
p1151
i have poor gas mileage, lack of power, rough idle, and almost seems after driving at a constant speed then letting off the gas to say get off an exit ramp, the engine will start jerking like it wants to die, maybe miss fire, then when you take off again it wants to jerk and buck, but straightens itself out and goes on, im at a loss, anything would be a help
thanks
Post Fiend
Joined: Jan 2003
Posts: 9,748
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From: Connecticut
Welcome!
Your truck's engine is running lean. That means it's either getting too much air, or not enough fuel. I suggest you do a search of this forum using the keywords "P0171" and/or "P0174" and you will come up with a lot of relevant information. Here's a couple of previous threads on the subject to get you going:
https://www.ford-trucks.com/forums/s....php?p=3314193
https://www.ford-trucks.com/forums/s...d.php?t=443055
You can look up Ford Diagnostic Trouble Codes HERE.
Your truck's engine is running lean. That means it's either getting too much air, or not enough fuel. I suggest you do a search of this forum using the keywords "P0171" and/or "P0174" and you will come up with a lot of relevant information. Here's a couple of previous threads on the subject to get you going:
https://www.ford-trucks.com/forums/s....php?p=3314193
https://www.ford-trucks.com/forums/s...d.php?t=443055
You can look up Ford Diagnostic Trouble Codes HERE.
Last edited by Rockledge; Jan 23, 2006 at 07:53 PM.
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I have a 98 4.0L Auto and I had a 1151 code, along with a missfire code. Turns out the Bank 2 O2 sensor was bad. It wasn't dead, just giving bad data to the computer. I had a mechanic discover this by testing the voltage.
Replaced the sensor (actually decided to replace all three) it runs great now.
Replaced the sensor (actually decided to replace all three) it runs great now.
Lead Driver
Joined: Jul 2004
Posts: 5,946
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From: in the woods of MA
im getting 3 engine codes
p0171
p0174
p1151
p0171
p0174
p1151
Both banks lean (and post-cat sensor lean too) is usually a fuel delivery issue, not a sensor issue. Could be a vaccum leak (lots of possibilities there, including the known issue of bad gaskets on the intake side), or could be something on the fuel side such as low fuel pressure. Could be the MAF sensor (someone check me out here - 99's use a MAF, right?) Look for something that affects both banks.
Good luck...
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thanks for all the info guys, here is what ive done so far, i checked all the o'2s and they seem to be fine, fuel pressure was at 65psi, im not sure what its supposed to be for a 4.0L, and i didnt seem to find any noticeable vaccum leaks, is there a check for the intake gaskets,
Lead Driver
Joined: Jul 2004
Posts: 5,946
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From: in the woods of MA
I'd try the obvious stuff first - hook up a vaccum gauge, disconnect and plug vaccum lines (like the power brake booster) and watch for changes in the vaccum. Then there are some old tried and true methods to detect vaccum leaks, such as spraying carb cleaner or using a trickle propane - you spray/feed gas aaround various parts of the intake listening for changes in the idel speed. But there are lots of spots in the new intake sytems that are hard to reach, so... There's a "high tech" approach where a smoke machine is used to put pressurized smoke into the intake, then you watch for leaks coming out of the intake. But it seems that the method of choice for the intake gaskets on the 4.0 is teardown and inspection. Iv'e never done one myself, but from what I understand they're not that bad to do...
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Post Fiend
Joined: Jan 2003
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From: Connecticut
Good advice on checking for vacuum leaks. Don't forget to check the PVC and EGR systems for air leaks, too.
Regarding the MAF, try cleaning it: https://www.ford-trucks.com/forums/s...hreadid=126093
Regarding taking apart the upper part of the engine, this PDF article shows what you need to know if it comes to that:
Replacing Upper Engine Gaskets on a 4.0L OHV
Regarding the MAF, try cleaning it: https://www.ford-trucks.com/forums/s...hreadid=126093
Regarding taking apart the upper part of the engine, this PDF article shows what you need to know if it comes to that:
Replacing Upper Engine Gaskets on a 4.0L OHV
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Post Fiend
Joined: Jan 2003
Posts: 9,748
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From: Connecticut
Originally Posted by pawpaw
The fuel pressure number you posted is high.
My manual lists 35-45 psi as the normal range.
My manual lists 35-45 psi as the normal range.
Lead Driver
Joined: Jul 2004
Posts: 5,946
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From: in the woods of MA
Awesome link/doc, Rockledge; my kid has a '97 4.0L - it's not busted, but now that I have a copy of that doc I might take it apart just for the heck of it!
Is this site great or what...
Is this site great or what...
Post Fiend
Joined: Jan 2003
Posts: 9,748
Likes: 16
From: Connecticut
Originally Posted by NewEnglandHerdsman
Awesome link/doc, Rockledge; my kid has a '97 4.0L - it's not busted, but now that I have a copy of that doc I might take it apart just for the heck of it!
Is this site great or what...
Is this site great or what...
I put it together when I replaced my Ranger's upper engine gaskets:https://www.ford-trucks.com/forums/s...d.php?t=232373
BTW, I've seen a few threads wherein guys with a '97 4.0L had the same PO171 and P0174 lean codes. The problem in their case turned out to be a bad fuel supply manifold gasket. Seems that the '97 models got a certain type of gasket there that would fail and get sucked into the lower intake. There's even a TSB on it that I mention in the article. Interestingly, the TSB indicates that it's only an issue on the '97. I'm sure if you do a search you can find the threads.
Just a heads up in case your kid's '97 starts throwing those pesky lean codes.
Last edited by Rockledge; Jan 24, 2006 at 09:08 AM.
Moderator
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From: SW Va
Thanks for the FP update Rockledge, the correction for the 99 is duly noted in my manuals fuel system specifications page.
Yet another important thing they neglected to update!!!!
Yup, then this sure sounds like a vacuum leak problem.
Mustang347cid, did this problem come about suddenly after some event, or slowly over time????
Yet another important thing they neglected to update!!!!
Yup, then this sure sounds like a vacuum leak problem.
Mustang347cid, did this problem come about suddenly after some event, or slowly over time????
Lead Driver
Joined: Jul 2004
Posts: 5,946
Likes: 62
From: in the woods of MA
Let's see if I can get this link stuff right...
https://www.ford-trucks.com/tsb/tsb.php/m-FORD/d-RANGER/y-1999/t-01205
This same bulletin seems to show up in lots fo other palces too, 2000 Excursions, 2001 Escorts, etc., so it doesn't appear to be limited to 97 Rangers
https://www.ford-trucks.com/tsb/tsb.php/m-FORD/d-RANGER/y-1999/t-01205
This same bulletin seems to show up in lots fo other palces too, 2000 Excursions, 2001 Escorts, etc., so it doesn't appear to be limited to 97 Rangers