I have 2001 E-150 with 5.4L 122,000 miles
the Mileage is has been running around town is around 7 Highway 10, Just recently I got a check engine light and using a low cost Code reader got the engine code P 0136 (oxygen sensor)
The Mileage has been poor prior to the Check Engine light and the code reader reveled no codes
any suggestions

 

The P0136 code is regarding the oxygen sensor after the converter on bank 2 as having an oxygen sensor heater circuit fault. This needs to be corrected before doing anything else. It could be the sensor or the circuit supplying power to the heater in the sensor. If you want to , you can try replacing the sensor and if the code comes back further testing will need to be done to find why the heater circuit is not getting power.

 

Agreed however the van exhibited poor mileage prior to receiving the code, I'm wondering if that would resolve the mileage issue, and should I replace all the sensors?

 

There could be other reasons for the poor mileage, but if you want to , you can replace them all at once. Best to get OEM sensors, but they will not be cheap.
We usually don't replace them unless there is a code or some other reason.

 

Thanks for your suggestion. Need a recommendation for a good basic code reader, the one I'm currently a cheap Ionnva reader.

 

It depends on how much info you want, how much you can do and last,,,,how much you want to invest.

The more a scan tool can do , the higher the cost.
Not knowing where you reside, but a lot of places will obtain codes at no charge, hoping you will purchase the item that MIGHT correct the reason for the code.

You can start with a cheapie, graduate to a little higher cost reader, then on to a scan tool. When you look at the total,you might do better to spend a little more once and get more for your hard earned $$. Personal ambition will determine just how much you want to invest.
It sure beats running to a low cost place every time a code comes up, so doing some research will help a lot..
What is nice about a basic scan tool that will provide data stream info is ,,,you can look at and get an idea of what normal readings might be so when a problem comes up you will see what is different and go from there..