1998 Explorer 4.0 lean banks 1 & 2.

[rsmustang50]

which ones are banks 1 and 2.

 

[Gus Gorilla]

Don't hold me to it with a stick, but I'm pretty sure that would be the whole engine, Bank 1 being one side and bank 2 being the other. I'd start looking for a vacuum leak as the cause.

 

[rsmustang50]

i have looked for vacuum leaks but have not found any. the parts store said i could be 02 sensors?

 

[originalnitro]

bank 1 left (driver) side
bank 2 right (passenger) side

 

[rsmustang50]

i think it has timing chain rattle to. it has 150k miles. could that be part of my lean problem.thanks

 

[originalnitro]

never heard of a timing chain causing a lean problem

 

[originalnitro]

would check for vacuum leak where the intake bolt to the heads 4.0 are known to leak there.

 

[rsmustang50]

first thing in the morning when i start it. it will shake and sputter and then die. after it warms up it runs fine.

 

[originalnitro]

sounds like a intake leak,4.0 use o-rings for gaskets they shrink and crack when cold,expand and seal up when warm and run fine change gaskets

 

[rsmustang50]

i will try that thanks

 

[jd3z400]

maf

 

[BrooklynBay]

Welcome to this forum! I've moved your thread into the stock 95-01 section. It sounds like the intake manifold gaskets are leaking. What are the code numbers?

 

[rsmustang50]

it was misfire on number five cylinder and lean banks 1 and 2.

 

[AmsoilGuy]

fuel pump. Does it hesitate in the upper rpm range and bogs out?

 

[rsmustang50]

no it runs great after warming up.

 

[syn-]

The only way this could be your MAF is if you increased the size of the housing, which may not actually be the case. I would go with what originalnitro said, replace your intake gaskets. I have an OHV and this was my problem despite me increasing the MAF housing, had those same exact codes (including the misfire in cyc 5).

 

[2000StreetRod]

banks & MAF

bank 1 is on the same side as cylinder #1 (passenger).
bank 2 is on the driver side.
Increasing MAF sensor housing diameter results in lean mixture on both banks when PCM is in closed loop.
If your MAF sensor and housing is stock then I agree that you probably have an intake leak.

 

[rsmustang50]

it is all stock

 

[originalnitro]

bank 1 is on the same side as cylinder #1 (passenger).
bank 2 is on the drivers .

ford service tech told me the opposite so which way is it really

 

[2000StreetRod]

Ford service tech

ford service tech told me the opposite so which way is it really

Find another Ford service repair shop!