4.0 Issue

cllake

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2000 Ranger 4.0

I bought the truck with a misfire, thought it was the injector so I changed it. It ended up having cracks in a head. So, I replaced the head and the truck ran better for a day or two. Now it is stuttering, the idle is a little off and it has low power. It is throwing codes P0171 and P0174. I have checked for vaccum leaks and ford has verifed their are none. Their are 2 brand new O2 sensors with less than 2,000 miles. The MAF is clean. I broke down and took it to ford and they 'think' it 'might' be the lower intake gasket.

SO, what do you guys think it could be? Should I just pull the intake this weekend and change the gasket?:confused:

Thanks for any and all help
-Cody
 

Wahl_7s

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What did they say the codes were? intake gaskets are actually o-rings! But don't be scared they are really easy:D. that said they usually don't go bad
 

Wahl_7s

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Ok I just looked up the codes po171&174 are lean codes on both sides of the engine so i would check the MAFS, that would be first, if the MAFS is bad the PCM defaults lean because it doesn't seance air flow to the intake. i'm pretty sure that's it:)
 

cllake

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Ok I just looked up the codes po171&174 are lean codes on both sides of the engine so i would check the MAFS, that would be first, if the MAFS is bad the PCM defaults lean because it doesn't seance air flow to the intake. i'm pretty sure that's it:)
There are multiple MAFs? I've only checked the one directly after the air box. Well, I've cleaned it atleast. Wouldn't that have been one of the first things the tech checked at Ford? I'll call Ford tommorrow and see if I can talk to the tech, the sales guy is a fing moron!
 

cllake

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To answer your first post, all the gaskets are new, i just replaced a head. The Ford tech was 'thinking' the lower intake gasket might have slipped when installed. Which I think is bull**BAN ME****BAN ME****BAN ME****BAN ME** because I took my time so I wouldn't have any problems..There is a possibility though..:eek:
 

Wahl_7s

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The codes said lean,you could also check fuel pressure should be at least 40LBS.how did you clean it? The fine hairs in MAFS are really sensitive,or maybe they broke! Google ford trouble codes, there are several things it could be check it out:D
 

Moss2

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To answer your first post, all the gaskets are new, i just replaced a head. The Ford tech was 'thinking' the lower intake gasket might have slipped when installed. Which I think is bull**BAN ME****BAN ME****BAN ME****BAN ME** because I took my time so I wouldn't have any problems..There is a possibility though..:eek:
Before tearing it apart spray some solvent or starting fluid where you think the leak is and see if it picks up RPM or stumbles and sputters. Dont set your car on fire with crazy spraying of flammables though.

Did they check fuel pressure. A couple of my Fords showed lean codes when the fuel pump was toast.
 

Sparky

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Or the hose between the MAF and the throttle body. Managed to wear a hole in mine and it threw the same codes.
 

cllake

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Trying to find a fuel pump to fit my budget, or lack off lol I'll let you guys know what happens.
 

Slippery P

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Dont go spending all your money on a fuel pump yet. Its possible that the lower intake gasket did not seal. Its a better bet that one of the upper plenum o-rings rolled when you installed the upper plenum. If your truck has egr, where the egr tube enters the upper plenum that o-ring can roll or become pinched very easy when installing the egr tube. I would suspect a vaccum leak before anything. If you can get your hands on a scan tool monitor the O2 sensor pids for both banks while spraying carb cleaner around the upper and lower intake gaskets, when they peg rich (.90volts) their is your vaccum leak.
 

cancinoj

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we had the same problem, well, it end up to have the o2 sensors connected the wrong way, the left on the right and viceversa, check for voltage and that had connected the right on the right and left on the left, ha, that was our problem, believe it or not, that solve all our engine problems, so far, smoth as new.
 
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