Running Flat / Dead

[94expo]

Driving on long trips After maybe 60 to 100 miles after Going up long Hill/upgrades 1 mile or more then Going down the other side My 94 starts running Dead or flat. I kick it down and it takes off and runs fine then return to normal and it starts running dead again. This will contiue for a few miles then clear up. I also get a CEL at the same time. then goes out when the thing starts running fine. Code are: O2 reading lean bank 1 / O2 reading rich bank 1 / O2 reading lean Bank 2 / O2 reading rich Bank 2. Not sure if Both O2 sensors are bad or something else causing this problem. Other than that the trucks running Great.

 

[88vert]

How is your gas mileage?

 

[94expo]

Getting 23 MPG

 

[88vert]

Thats great mileage for an ex You might want to change number one 02 sensor first,that would be the one closest to the motor

 

[94expo]

The MPG was figered from a Road trip from LA to Vegas. there's two O2 sensers right. One on the left and one on the right.

 

[88vert]

Yeah you have two you want to change the one closest to the motor first.

 

[94expo]

But if im getting a CEL on Bank 1 and Bank 2 wouldn't that indicate a problem with Both O2 sensers?

 

[Opera House]

Great gas mileage

I suspect it is your fuel pressure regulator. Mine had that problem. The thing I miss is the really great gas mileage. Some of these regulators have the spring slightly off center and it wears the seat only on one side. This causes the valve to slightly stick open sometimes. The computer then tries to compensate. A quick repair and about $60 aftermarket. Oh, but you will miss that gas mileage!

 

[94expo]

Are you saying if it is my fuel pressure reg and I change it out I will lose gas MPG?

 

[Opera House]

Yes, if that is your problem

But it will keep you from burning a piston or valves. Part of the economy is from a really lean burn and part is from a less aggressive driving style that you may have adapted. I know when mine got fixed, I drove more agressively. You'll be hard pressed to find any one else that claims 23 mpg in an Explorer. Just want you to be aware that some pressure regulators wear unevenly and cause very strange problems. Pressures will often test normal except durring the condition. I was looking for an electrical problem so I was monitoring pump current when I found that it would drop to less than normal. Current is proportional to pressure. Flow is pretty much constant because the fuel that is not used by the engine is returned to the tank. This is a high bypass system. Pressure is controled by vacuum. Idle is the lowest, highest on acceleration. If you are driving along and see the current drop, it is probably the regulator. If you change it, you must reset the computer by disconnecting battery.