Error code
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Error code
I have a 99 F150 running Lean on bank 1 and bank 2 i have replaced PVC hose , Replaced Mass Air Flow sensor and it started running worse then before i changed (MAF) what else can i try to fix this problem ?
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From: Corona, Crazyfornia
There are alot of things that will bring up the lean codes, I an assuming that you have a P)0171 & P0174 right?
Just some examples:
Exhaust leaks (cracked manifold and such)
Various vac leaks
Bad brake booster
Bad vac line to the booster
Cracked vac resivore (sp) (the little black ball thingie)
Bad intake gaskets
Bad intake manifold
Heck even the Hose from the throttle body to the air cleaner being cracked or loose will do it.
And the list goes on. You said it runs worse after you replaced the MAF, did you reset the computer? And what are the exact codes you have? Any other besides the lean codes?
Just some examples:
Exhaust leaks (cracked manifold and such)
Various vac leaks
Bad brake booster
Bad vac line to the booster
Cracked vac resivore (sp) (the little black ball thingie)
Bad intake gaskets
Bad intake manifold
Heck even the Hose from the throttle body to the air cleaner being cracked or loose will do it.
And the list goes on. You said it runs worse after you replaced the MAF, did you reset the computer? And what are the exact codes you have? Any other besides the lean codes?
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Yeah i reset it after i changed the (MAF)and it ran worse so i put the old one back on and it ran petty good for about 25 or 30 miles then the light came back an started running bad again .. Yeah 171 and 174 are the only two codes that keep coming up over and over again , tried brake cleaner around intake an vac lines but it didn't rev up any checked o2 sensors checked the cats but now im just at a lost to what it is ....
Technical Article Contributor
Joined: Oct 2005
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From: MI
Most common problem for those DTC's is a PCV line leak between the back of the upper intake manifold and firewall. Yea, it's not the MAF when both banks are positive for lean.
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If both banks are lean you have to look at what could effect both.
Depending on intake style, bad Intake gaskets
Bad Throttle body Gasket
Bad Vac Hose (possibly and usually PCV hose)
Dirty MAF
Things that will effect one bank but not the other
Bad Injector O Ring
O2 Sensor
depending on style of intake, Intake gasket
Technical Article Contributor
Joined: Oct 2005
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From: MI
Well first things first. The things that won't cost yuh from mis diagnosis.
Like I said, check the most common. The PCV at that point/spot. You have a 99 F150 with a 5.4L. The generic for all Ford engines doesn't always apply. Yes, Ford has it that the MAF is the common culprit, but, this is a F150 forum therefore you may receive information specific for such and some may post what works for other engines within Fords line.
The truck lines w/v8's , - The PCV system is most common. To add, the Intake gaskets are less likely when both banks test positive, - at the same time.
To correct my post earlier, yes, it is possible for the MAF to be at fault. In my experience with these particular trucks, it's a leak. Also check IAT grommet and MAF O-ring. That O-ring needs to have a good seal. So does the Air intake.
Like I said, check the most common. The PCV at that point/spot. You have a 99 F150 with a 5.4L. The generic for all Ford engines doesn't always apply. Yes, Ford has it that the MAF is the common culprit, but, this is a F150 forum therefore you may receive information specific for such and some may post what works for other engines within Fords line.
The truck lines w/v8's , - The PCV system is most common. To add, the Intake gaskets are less likely when both banks test positive, - at the same time.
To correct my post earlier, yes, it is possible for the MAF to be at fault. In my experience with these particular trucks, it's a leak. Also check IAT grommet and MAF O-ring. That O-ring needs to have a good seal. So does the Air intake.
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the pvc hose was the first thing that i replaced ( which it was dry rotted and cracked so it needed to be replaced ,then i bought a can of MAF cleaner that didn't work so i replaced the MAF an that made it run worse so i put the old one back on an reset the light then it was about 30 miles later it started doing it again so i used brake cleaner all around the intake an all over the vac. lines an there was no change in the rpm's so know i need to check the other things that bring up this issue ....
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well it is running better but after i reset the light i got about 20 miles on it an it and the light camr back on with the same codes 171,174 lean on bank one and two .... so i kinda just quit messing with it for now .... but thamks for all of your advise an help
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i have changed the pvc,maf,three vac. lines and the intake gasket and still have same problem as i did before i changed the first part ...... Do you have any more ideas on what it could be ??? If so put them in a list and I'll go down them one at a time until i get it fixed .... I'm putting more money into the truck than what it is worth LOL
