Check engine Light

[Fordsgalore4]

Ok I just brought my 2001 EB 4.0 SOHC out of storage for the past 3 months its got 97,250 miles on it and is a 4x4 after driving it for a few days it pulled a CEL two codes P0171 system too lean (Bank 1) the second P0174 system too lean (Bank 2) In my passed if it was one of the sides it a bad O2 but this time its both sides at once the only thing that I can think off is the Mass Air Flow sensor Iv all ready cleaned it and it seems fine but I wanted to ask and see before I have to go buy this very expensive part thank you for any advice

 

[koda2000]

Ok I just brought my 2001 EB 4.0 SOHC out of storage for the past 3 months its got 97,250 miles on it and is a 4x4 after driving it for a few days it pulled a CEL two codes P0171 system too lean (Bank 1) the second P0174 system too lean (Bank 2) In my passed if it was one of the sides it a bad O2 but this time its both sides at once the only thing that I can think off is the Mass Air Flow sensor Iv all ready cleaned it and it seems fine but I wanted to ask and see before I have to go buy this very expensive part thank you for any advice

the SOHC engine is infamous for having these lean codes. it usually indicates the intake manifold o-rings are dried, stiff and have shrunk. this causes them to leak air. the only thing to do is replace them. the gaskets/o-rings are fairly cheap and it takes a couple of hours to change them if your handy. be sure to do both the upper and lower gaskets.

 

[Fordsgalore4]

the SOHC engine is infamous for having these lean codes. it usually indicates the intake manifold o-rings are dried, stiff and have shrunk. this causes them to leak air. the only thing to do is replace them. the gaskets/o-rings are fairly cheap and it takes a couple of hours to change them if your handy. be sure to do both the upper and lower gaskets.

Man I just change them a few months ago when I had to replace the timing tensioners well looks like its back under the knife again

 

[2000StreetRod]

EGR tube O ring?

The O ring that seals the EGR tube where it enters the upper intake manifold also becomes brittle with age. It often breaks when removing/installing the upper intake manifold.

Some members break the flexible elbow just upstream of the IAC valve when removing/installing the upper intake manifold.

Also, check the EGR valve gasket for leaks.

 

[RKH58]

The O ring that seals the EGR tube where it enters the upper intake manifold also becomes brittle with age. It often breaks when removing/installing the upper intake manifold.
View attachment 79942
Some members break the flexible elbow just upstream of the IAC valve when removing/installing the upper intake manifold.
View attachment 79943
Also, check the EGR valve gasket for leaks.

Would this also cause those two codes to come up? Just had my intake gaskets done a couple months back and it's throwing out p0171 and p174 again.

 

[2000StreetRod]

5 years?

Assuming that quality gaskets were used I suspect it would take at least 5 years for new ones to dry out and shrink enough to generate those lean codes. If the vehicle has been unused for an extended period and the lean codes did not occur before the unused period I suggest checking the fuel pressure.

 

[lobo411]

Check the torque...brand new gaskets won't do anything if the bolts are loose.

 

[Fordsgalore4]

The gaskets set I used was a Felpro there about 5 months old the bolts were torqued down and the truck did sit for 2 months this summer June to 1st of Aug The ex runs great and I'm actually getting better MPGs since the light came I'm going to have to pull the intake again and check the upper and lower gaskets and check the EGR o ring and the gasket for the EGR it self and look at the IAC valve to thank you guys

 

[koda2000]

The gaskets set I used was a Felpro there about 5 months old the bolts were torqued down and the truck did sit for 2 months this summer June to 1st of Aug The ex runs great and I'm actually getting better MPGs since the light came I'm going to have to pull the intake again and check the upper and lower gaskets and check the EGR o ring and the gasket for the EGR it self and look at the IAC valve to thank you guys

you're getting better mileage it's because your introducing more air into the engine. the problem with this is it increases cylinder temperature, which can damage your engine. Felpro makes very good gaskets, perhaps when you take it apart again, you'll something find a pinched o-ring or damage sealing surface. check everything carefully. while your in there check for any other possible sources for vacuum leaks. PCV elbow is a weak point, PCV grommet, any vacuum hose or connection, a bad power brake booster. also, if you haven't changed you fuel filter in a while (Ford recommends every 30K miles, i do mile once a year) some have reported that this can cause the P0171/174 codes i guess through fuel-starvation.