We have a 2004 Escape with 127,XXX miles. Over the last few months the fuel mileage has gone from bad to terrible (around 14-15 mpg mixed city/highway). I have also been plagued with multiple o2 sensor fault codes.

I have replaced all 4 in the last 5 months and I am on my third Bank 1 Sensor 2 (Rear post Cat in the Y pipe) after multiple P0136 codes. Today the code is back once again.

Does anyone have any suggestions? The connector is clean and all the wires appear to be intact. Sensors we replaced with Bosch. All filters/fluids/plugs have been changed in the last year. Tire pressures are all good. Runs smooth at idle, no additional codes from a cheap reader.

It's my wife's car and I know she can be a little heavy on the gas pedal but there is not much difference between her last tank and mine while driving it last week. She has complained about less power but I can't notice any difference however it is anxious to hop out of overdrive at the slightest increase in pedal pressure and reluctant to drop in under 45mph (can't remember if this has always been the case) Last summer we did tow a small pop-up camper (less then 2500#) on a 2 hour run on relativity flat terrain. Does anyone have any suggestions? -Thanks

 

A code P0136 may mean that one or more of the following has happened:

Faulty O2 sensor leak in exhaust close to O2 sensor.
A short to voltage on O2 signal circuit.
Open in circuit resistance caused by corrosion in connector.

 

You have the code, but not any 'running' data. If I were checking, I'd get a scan tool that can tell me what is going on a bit more. You can watch the 'fuel trim' change as the O2 flip-flops, and see the 'load' on the engine as far as the engine 'thinks' it has one.
A MAP sensor could be telling the computer you are under a lot of load, for instance, and juicing up the fuel flow to make up for it. The MAF measures air flow into the intake, as far as it 'knows', but if you have extra coming in from a leak, the computer will not know that, and the mix will be off, and then 'modulated' by the O2 doing some tuning.
Check the fuel pressure also, as the computer may say 'spritz for .001 second', and it does, but the pressure is higher, and it sprays more fuel than expected. The computer in that case could be trying to cut back, {I know, on a diet...}, but can only do so much to reduce flow. If the pressure is too high, ... well, you get too much fuel.
tom

 

Thanks Tom,
The o2 sensor should still be under warranty so I'll change it out... again and check all my connections with a good dosage of contact cleaner.

Any suggestions on a reader to borrow/purchase? Once I locate one, is there a place to find acceptable parameters for this vehicle to compare my readings against?

-Chris

 

I have no brand to recommend. Search ebay and if local to a harbor freight, you may find something there that will fit your needs. Much as I'd like to buy Kobalt or Craftsman or Snap-on for their quality, sometimes it is just not smart. If I only use a tool once a year or for a special project, I'll sometimes get the bottom of the barrel, and figure it will last for my one use, and if I loan it out, or it breaks soon, I won't be upset.
As long as the scan tool will show the live parameters, then I can live with a small display or unwieldy set of buttons.
I don't have a set of numbers, either. I'd look at short and long term fuel trim, reported air, coolant, etc temperatures, and O2 workings/readings. You are looking for something that will cause a significant fuel consumption increase. Fuel pressure, regulator, duty cycle, I can't name all the things to look at. If you are lost, seek professional help, or ask a knowledgeable neighbor.
tom

 

I Replaced the faulty o2 sensor... again. Ended up re-locating the connector in the process. I have begun to have a small oil leak low on that side of the motor and it is being flung off the drive shaft right into the connector.

I purchased a different reader for my laptop. It shows a 30% load @ idle. I replaced the Plenum gaskets and PCV valve thinking the increased load reading is from a vacuum leak. After the above replacements there was no change. Tried removing all hoses in the intake one by one and quickly plugging them to see if there was any change in the reading with no success. Anyone have any suggestions or is the high load at idle normal with this vehicle? My Impala and Tundra are around 5%.

o2 sensors are all jumping around again and from what I can tell from looking online are with-in range.
-Thanks

 

I have some scanner readings from my '09, at idle between 36%-47%.

 

Thanks for the range. Got about 10 miles on the new o2 sensor and the light is back on with the same p0136 code. I think I am going to take out my extension splice and put the connector back in the original location and let the stealership look at it this week. Anyone on here ever had a problem with one of these eating sensors so quick? Other then a computer problem I am at a loss as to what is causing this.

 

I fixed my wife's 2001 Escape (v6 4x4) w/ 195k that was throwing P0136 by replacing the plugs and coil packs. Coils can be BIG $$$$ but found a set of 6 for ~100$ on a certain popular auction site.

I think O2 sensors are the most unnecessarily replaced auto part of all time. They are usually doing what they are suppose to do by reading a rich or lean burn. In our case the outta wack O2 reading was caused be a cylinder not firing because of a bad coil pack.


Cheers, Mac